At the “Rocks” Scribbly Gums were full of Varied Sitellas
while below all the convicted women and fellas
were stunned as, ne’er in their lives had heard
such magic as the mimicry of the Superb Lyrebird

Where the AMP building stands tall today
the Gymea Lillies and Banksias once held their sway
on the bush floor the Scrubwrens would “chit chit” and play
and in treetops Koalas still napped all the day

I imagine the cool of the fern lined Tank Stream
and Fig trees and Blackbutts where Bell Miners chime
made a pleasant backdrop for the local Bowerbird’s lair
yes, the Regent, who dwelt there that time

The entrancing magic of the new dawn chorus
revealed countless species yet to be named all before us
The Parma Wallabies dashed around lower George Street
where the Cadigal people you would perchance meet

If you happened to wander up to Martin Place
you might have met more folk from that other race
not foolishly proud, just getting by as best
as one would imagine in this giant virgin forest

I dream of being there in “New Sydney Town”
where no steel had yet touched a tree
and Musk Lorrikeets wheeled o’er Elizabeth Street
making vivid displays as they called happily

Topnot Pigeon flocks, hundreds strong, made an incredible sight
over what is now choked with traffic by day and all night
and whereupon Australia Square can be found
the Grey Kangaroo mobs used to abound

All along Pitt Street where the gums were in blossom
every hollow contained a small glider or possum
and the spotted quolls still reigned predatory supreme
or perhaps a goanna on the banks of the long lost Tank Stream

I dream of that time in “New Sydney Town”
every time that I stroll ’round the Quay
of a morning’s delight when Golden Whistler calls
announced their challenge from every tree

But then the new noises replace those old lost calls
and the Tank Stream no longer tumbles and falls
between green mossy boulder and pleasant cool glade
as all I can see is now mostly man made

My vision has faded to newer women and fellas
all prisoners now of employers, gadjets, auto tellers
with ne’er a moment to dream or perchance cogitate
on a magic morn lost in time: January 27, 1788

Ricki Coughlan 2004

SOME HAVE BILLS for probing and gleaning, whilst others are designed for hooking, tearing and prising. However their bills come, it appears that the Australian birds which make bark foraging their speciality have one thing in common: “Intraspecific Resource Partitioning”.

Many birds will opportunistically take an insect from a tree’s bark or perhaps even tear off a considerable amount of bark in search of a boring grub, as is the case with Yellow-tailed Black Cockatoos. I’ve frequently observed Grey-crowned Babblers in north-west Australia as they’ve torn open masses of bark to get at termite colonies. However, these birds are not specialist bark foragers. Those who have made searching amid or under bark as their almost sole means of finding a meal is quite an exclusive club in Australia. It consists of the Treecreepers (mostly), Varied Sitellas and the shrike-tits. Here in the Sydney region, it is the White-throated Treecreeper, Varied Sitella and Eastern Shrike-tit which we are likely to encounter.

We’ll begin our exploration of this fascinating topic by getting to know a little more about these birds which enjoy its benefits.

VARIED SITELLAS are cooperative breeders, with the young of previous seasons frequently assisting their parents in raising the young of subsequent seasons. Thus they are mostly found in foraging parties of at least 4 birds. It is generally concluded that the primary parents are monogamistic – staying together and probably not straying into the realms of cuckoldry or divorce too much.

Varied Sitella © 2006 Nevil Lazarus

This species is a remarkably acrobatic one which can be observed working their way around trunks and branches in a spiral fashion as they poke and prise with their specialised bill, which is quite upturned and very laterally compressed. It’s always a pure delight to hear the chittering calls of approaching sitellas and observe them flying from tree to tree with their conspicuous orange wing stripes giving them an almost butterfly-like appearance.

EASTERN SHRIKE-TITS, with their gorgeous colours, jaunty crests and industrious foraging style are a favourite with birdwatchers on the eastern seaboard. Whilst not being cooperative breeders, they are also monogamists and their young will often remain with them for extended periods as they learn the gentle art of ripping, tearing and prising at bark. Indeed, they are generally first detected by the sound of ripping bark in trees overhead.

Shrike-tits have two obvious styles of song, but each one differs from the other so greatly that it’s hard to believe they are made by the same species. One call sounds a little like the Brush Cuckoo: a series of high pitched but descending notes – “peer, peer, peer, peer, peer”. Their other song is what I call the “Flipper Call”, as it sounds like a dolphin or a weird chuckle: “eee-oooh-eee”. Shrike-tits are quite a confiding species and so will frequently forage in very close quarters to human observers.

WHITE-THROATED TREE-CREEPERS are our third of the bark foragers found around Sydney. Usually the first sign that one of these birds is in your presence is their loud, repetitive call which has quite a ringing quality to it.

A White-throated Treecreeper makes its way up a trunk. © 2006 Nevil Lazarus

Spending your entire life hanging off the side of a tree may appear to be a prodigious feet of strength. However, the treecreepers have come up with a simple system which allows them to achieve this: very long claws on their back toe, or “hallux”. This serves as a prop for these birds as they work their way up the trunks of trees. It can be seen quite clearly on the image to the right. Because of their specialised adaptation for climbing, they always work upwards in a somewhat jerky, almost skipping, motion.

A curious feature of the White-throated Treecreeper is that they spend a great deal of time listening for their prey. You will frequently see them with their ear against trunks and branches as they listen for borers and other prey hidden in crevices or beneath the bark. I’ve noted that in the southern part of their range (Albury & Chiltern, Victoria) that they don’t listen so much, but rather engage in a great deal of wing flashing, perhaps to startle prey off the surface of the bark or from within tight crevices (some cool papers in that lot for an industrious student).

Resource Partitioning

IT MAKES good sense to remain with the one partner for life as it does away with investing too much energy in courtship. However, another problem arises when remaining in close proximity, whilst sharing limited resources: How to share these limited resources without competing with each other? This is especially important, because if a territory is good for bark foraging, then there’s going to be plenty of other birds looking to get in on the action too.

One way of achieving this is for some family members to specialise in foraging in one part of a tree and for other family members to specialise in other parts of the tree. It means that families and partners can forage in close proximity but also find enough prey to maintain themselves. This is called “Intraspecific Resource Partitioning”. If their needs or behaviour diverges significantly, each generation of birds might begin to develop bills which reflect their slightly different lifestyles. Sometimes we see many species of birds sharing the same feeding resources but in different ways, such as in the case of waders on mudflats, where bill differences among sandpipers are very marked. This is known as “Interspecific Resource Partitioning” (more on this here) .

Resource Partitioning can be a great way of reducing the territory size required for a pair to survive, meaning that more individuals can make a living across the species’ distribution and all individuals waste less time defending the borders of large territories. This is exactly what our Aussie bark foraging specialists have done. Each of these species of birds will mostly be found foraging on different parts of the tree according to their sex. Generally it is the males on the trunks and larger branches and the females on the twigs, leaves and smaller branches. Of course there are frequent cross-overs, but the general rule becomes very clear to astute observers. On more than one occasion I have also observed Eastern Shrike-tits teaching their young to forage and it would appear that the adult males take the young males with them and the female adults take the young female fledgelings out with them. This practice is known as “Brood Divisioning”.

Eastern Shrike-tit bills tell the story

White-throated Treecreepers often don’t forage as a tight family unit, but if you ever see a male and female encounter each other on the same tree, the male will rigorously enforce his “trunk foraging rights”, chasing the female bird off to her special place on the tree. Varied Sitellas are even less strict with their Resource Patitioning, but it does take place. However, Eastern Shrike-tits are very determined Resource Partitioners.

I wanted to see how much the different foraging practices of the male and female shrike-tits had shaped their bill morphology. To investigate this, I paid a visit to the Australian Museum’s Bird Department. The Australian Museum has a fantastic storehouse of “skins”, “pickles”, skeletons, wings, eggs and feather specimens which scientists from all over may visit and study in order to build our understanding of birds. Gruesome as it appears to be, “collecting” these birds plays an important part in our understanding of each species and assists us with the kind of knowledge required that helps us work towards conserving the world of nature. A well prepared “skin”, or specially stuffed bird, can last for well over a century and contribute much to our knowledge.

I met with Curator of Birds and well known Ornithologist, Walter Boles, who availed me of his Eastern Shrike-tit collection for a little bill comparing.

two adult Eastern Shrike-tits, both sourced from the northern beaches region of Sydney in the early 20th century. Note that they are of similar size overall. The male bird, on the left, has a black throat and the female has the olive throat, but take a look at the striking difference between their bills. They're certainly fashioned for performing different tasks. © 2006 Ricki Coughlan, courtesy of the Australian Museum.

Sure enough, an obvious difference between the bills of the males and females of this species does exist. The fact that they forage in differing parts of trees and in different ways has shaped the appearance of their bills accordingly. This demonstrates a solid dedication to resource partitioning. Another scientist, Dr Richard Noske of Charles Darwin University in Darwin, has studied Eastern Shrike-tits and found that there was a seasonal aspect to their foraging strategies and that this could also vary from location to location¹. All this points to the best use of resources and ensuring that various nutritional needs are met by the birds during times of feather moulting, courtship, feeding young and recovering from their arduous breeding season.

Next time you encounter any of these fantastic birds when you’re out and about, spend a little time observing their foraging behaviour. It makes you wonder: Is there anything these amazing creatures haven’t come up with?

Until next time . . . happy birding!

References:

1. Noske, RA, Sexual differences in the foraging behaviour of Crested Shrike-tits, Falcunculus frontatus, during winter, Emu 103(3) 271 – 277

Since Europeans visited Australia they have engaged in large land clearing projects both for farmland and to accommodate the urban sprawl. The result has been fragmentation of bush in urban areas and the influx of exotic plants and animals.

Because birds are mostly diurnal and many are relatively easily studied we are developing enough understanding about how they relate to their environment to help tell us about the health of urban bush reserves, making them an important management tool. Two species of Little Brown Bird which can be found in the Sydney region may be particularly valuable in this regard: The Brown Thornbill and the Striated Thornbill. If we examine their lifestyles, this becomes very clear.

IT’S AN interesting fact that the smaller the bush fragment, the less likely you are to find Striated Thornbills in it, though Brown Thornbills may still be present. Here on Sydney’s Northern Beaches, there are no Striated Thornbills in any of the council reserves. However, they are present in Garigal National Park (including Narrabeen Lagoon catchment) and around Ingleside in Kuringai National Park. I believe that some may be present in Ingleside Park on the escarpment overlooking Irrawong Reserve.

Fascinating Striated Thornbills

THE STRIATED THORNBILL has a very interesting lifestyle. Like many of the Australian thornbills, the Striated Thornbill is a cooperative breeder. However, they have a unique approach to this. Striated Thornbills spend most of the year in large extended family groups numbering between 20 and 50 individuals. During those months they remain for the most part in the forest canopy levels where they forage for small invertebrates.

Striated Thornbills are generally canopy foragers for most the year. Thornbill image © 2006 Nevil Lazarus.

From late August to mid October they form small family groups, comprised of a breeding pair and two or three helpers which may be their offspring from the previous breeding season. They construct a beautifully woven nest of bark, roots, lichen and grasses and raise mostly three young, with all the helpers pitching in to provide food for the ravenous chicks, which follow the adult birds relentlessly as they beg for sustenance.

During these months the Striated Thornbills use every level of the forest, from canopy to forest floor, as they seek to find the food to keep up to the hungry chicks – and themselves. Each family in the extended family group, or tribe, builds a nest roughly 50 metres from its neighbours and so when the Striated Thornbills are breeding in a forest you’re really going to know about it, as the bush becomes a hotbed of these gorgeous little birds.

From August until November breeding Striated Thornbills forage in all levels of forests. Thornbill image © 2006 Nevil Lazarus.

If a family of Striated Thornbills fails in its attempt to raise its young, they simply move next door and help their neighbours raise their offspring. When the young are of a sufficient age to mostly care for themselves, the entire extended family joins up once more and moves back into the canopy where, if any young should still beg, any bird in the tribe will offer it a morsel.

The Odd Couples

UNLIKE MOST thornbills, the Brown Thornbill is a monogamous pair breeder (keeps one partner, perhaps for life). It is generally found in pairs in the shrub layer, or mid story of forests where it holds a territory which comprises of a given amount of shrubbery.

In undisturbed or large patches of forest, Brown Thornbills are mostly found in the shrub or mid-story layers. Thornbill image © 2006 Nevil Lazarus.

If the shrubbery is dense, it holds a smaller territory and if it’s sparse, the territory is larger. Both arrangements have their pros and cons. It has been observed that if the size of the reserve is small, that the Brown Thornbill will expand its territory to include the canopy and ground cover layers.

In smaller fragments, Brown Thornbills are found in all layers of the forest, bringing them into conflict year round with Striated Thornbills. Thornbill image © 2006 Nevil Lazarus.

Thornbill wars

So it is clear that at certain times of the year Brown and Striated Thornbills are going to come into conflict and I have witnessed many pitched battles between these birds, with the Striated Thornbills making all manner of unique war cries as they move through the shrub layer and gang up on the Brown Thornbills, sometimes with considerable success.

The average Brown Thornbill is 2 grams heavier than the average Striated Thornbill, For birds this small, that means that the “browns” have a significant advantage over their striated cousins when it comes to birdie pugilism. In smaller bush fragments, where Brown Thornbills move into the canopy – the regular domain of the Striated Thornbills – that they are simply too difficult to overcome for the Striated Thornbills, even when they have the weight of numbers.

Dispersal and gene flow

THERE IS STILL much to be learned about the dispersal behaviour and patterns of thornbills – at what age do they disperse? Do both sexes disperse at the same age? Do both sexes disperse? How far do they disperse? We do know that gene flow – the movement of individuals carrying genetic diversity from population to population – needs to be adequate to maintain robust health for all organisms and this includes thornbills. So how would a family group of Striated Thornbills deal with being trapped in a fragment of bush where it couldn’t receive an influx of fresh genes from others of its kind from further afield? There is a strong chance that inbreeding would occur, threatening the tribe with weaknesses which would make it less capable of dealing with disease and other ardours of life in the treetops. As the population in the fragment shrinks, the problem worsens.

Larger groups require larger resources to feed themselves, and if they’re constantly clashing with Brown Thornbills as they attempt to forage in shrinking reserves they’re likely to struggle to meet their needs.

Indicators of bushland health

Sydney's urban bushland is beautiful and unique. Understanding its ecology is vital if we're to manage it successfully. © 2006 Ricki Coughlan.

IT SEEMS TO ME that if a reserve is not capable of supporting Striated Thornbills, it might not be capable of supporting other species – further compomising the viability and quality of the urban bushland reserve, so we can understand that Striated Thornbills may be an important indicator of environmental health. For this reason, wildlife corridors and urban plantings take on an even greater importance. There are many bird species trapped in reserves which are not capable of crossing the human barriers to neighbouring bush. However, with appropriate urban planning and community education this problem can be overcome and also introduce many more birds into suburban gardens: a lifestyle boost for the birds and we humans – and our property values . . . now that’s an argument that should be easy to win!

In the next few weeks we’re going to look at the lives of other groups of birds with unique and interesting lifestyles which can tell us more about environmental health. These include fairy-wrens and bark foragers, like shrike-tits, tree creepers and Varied Sitellas.

Until next time . . . happy birding!

The East Asian-Australasian Flyway. © 2007 Ricki Coughlan.

From September to November each year millions of migratory shorebirds are making their way south to Australia from their breeding grounds in North Asia, Japan, Siberia and Alaska. Their flight path is the East Asian-Australasian Flyway: a massive aerial highway marked by prevailing winds and driven by a wonderful behavioural trait known as “site fidelity”.

Site Fidelity simply means that for the most part shorebirds are drawn to return to the same breeding and wintering grounds each year. This makes sense if you’re a migrant, because: a. it ensures that you work to the flight path that you have learned from the outset and; b. the “If you’re on a good thing stick to it” principle is a good one for survival.

All this means that for the past few weeks, and for a few more ahead of us, the coastal and inland wetlands of the Sydney region are enjoying an influx of shorebirds, after a depauperate winter, and the through-passage of a number of species which we don’t often see. We also get to witness plenty of birds with coloured leg flags and these are worth noting in detail and reporting: mintons@ozemail.com.au.

Awesome Long Reef

As reported last week, we’ve witnessed some fantastic shorebird diversity on Long Reef and Boat Harbour, beginning with our monthly shorebird count at Long Reef, where we witnessed the return of the Pacific Golden Plovers, Grey-tailed Tattlers, Red Knots and a nice influx of Ruddy Turnstones and Red-necked Stints: with plenty more yet to come.

A little diversity at Long Reef: tattlers, turnstone and Pacific Golden Plover. © 2009 Ricki Coughlan.

A BRILLIANT RARITY for the Sydney region was the Australian Pratincole, which a shorebird enthusiast reported at Long Reef through the week. They’ve been reported in the Hunter Region in the past, but this is the first incursion of this species in the Sydney region that I’ve heard of.

It's great to see the numbers returning to Long Reef and enjoy the sight of these fascinating birds as they forage in the shallows. © 2009 Ricki Coughlan.

Amazing Boat Harbour

Boat Harbour has become increasingly brilliant. First, with a steady influx in numbers recorded on my survey last week. These are possibly third year birds returning from their “practice run migration” to the Yellow Sea and back, but also with a number of species which are now pretty uncommon on the reef or bearing coloured leg flags that continue to inform us of their movements. I had reports of over 100 Sanderling on Boat Harbour through the week: a nostalgic sight it would have been, as thousands of these birds once wintered on the beaches of this area before the era of beach buggies, horses, dogs and 4WD vehicles.

This Sanderling appears to be getting over a somewhat arduous journey! © 2009 Ricki Coughlan.

We've had several flagged Sanderling at Boat Harbour of late. This one has the single orange flag, of a Victorian bird. We've also had South Australian Sanderling too. © 2009 Ricki Coughlan.

A Bar-tailed Godwit bearing a Victorian leg flag. Note that these birds are all in pretty heavy moult and plenty of feather wear. © 2009 Ricki Coughlan.

Stint numbers are increasing and we now have close to 100 birds on the reef. This will more than double in coming weeks. © 2009 Ricki Coughlan.

This week it was a further influx in numbers of Red-necked Stint and Ruddy Turnstone, but with even more Sanderling, a Red Knot, a Victorian-flagged Bar-tailed Godwit (and traveling companion) and a Lesser Sand Plover (also once common here prior to massive human disturbance).

We get a few Red Knots through every year and mostly it's during dispersal time. © 2009 Ricki Coughlan.

A Whiskered Tern in full breeding plumage is a gorgeous site - and a rare one too around Sydney. © 2009 Ricki Coughlan.

A now rare Lesser Sand Plover on Boat Harbour. Sadly, this image was the best I could do as the afternoon winds increased.

All in all, it’s a great time to head out onto the rocky headlands of Sydney, you really owe it to yourself to head down to Long Reef or Boat Harbour and catch some of the action!

Let’s conserve these sites!

Again, these events prove the incredible importance of these headlands to dispersing shorebirds, even though they may appear almost bereft of shorebirds in the winter, they are vital to these birds, which are completing exhausting journeys and are often desperate for a spot to shelter, sleep, feed and bathe towards the end of their long sojourn. Threats include destroying diversity through invertebrate poaching, excessive human disturbance on high tide roosts, fisher’s litter and unrestrained dogs. Constant education for the well meaning and compliance vigilance for the less intelligent members of the community who think they’re above instruction or doing the right thing is always required.

Until next time . . . happy birding!

We’ve gone from around 20 Red-necked Stints and a couple of Ruddy Turnstones, to almost 100 stints, 20 Ruddy Turnstones, several Pacific Golden Plover, 2 Grey-tailed Tattler and a Red Knot. Numbers can be expected to grow considerably in coming weeks.

Whilst counting today, around 50 of the Red-necked Stints departed the reef in a southerly direction. They didn’t return within 10 or 15 minutes, so we’re presuming that they’ve continued on their journey to wintering grounds further south.

This is yet another moment in this ancient and wonderful story which has been playing since long before a human footprint was placed on this earth. It’s been acted out on the cold and vast tundra of Alaska and Siberia, the massive mudflats of the Yellow Sea and the mudflats, wetlands, beaches and rocky headlands of Australia and all of the near endless skies in between. It’s a story which beckons us to explore the countless other stories which every species of life on this amazing planet has to tell. It’s a story which reminds us what a precious and wonderful little speck we find ourselves on: perhaps the only speck in the universe where anything remotely like the riches that we experience actually exist. We’ve risen to a position of custodianship on this planet: a position which holds unimaginable responsibility. Let’s hope that more people will learn this story of the migratory shorebirds and come to understand the importance of the decisions which we are all facing at this time in history.

Here’s a few images from today’s survey:

Two Grey-tailed Tattlers, a Ruddy Turnstone and Pacific Golden Plover catching a high tide snooze. © 2009 Ricki Coughlan.

Ruddy Turnstones, Red-necked Stints and a Red Knot (preening, top left) at their roost. © 2009 Ricki Coughlan.

Foraging Red-necked Stints. Note that these birds cannot see their prey, they're using highly sensitive bill tips to feel their way through the algae for tiny invertebrates. © 2009 Ricki Coughlan.

It was great to see so many stints foraging on the reef as the tide lowered. © 2009 Ricki Coughlan.

Brown Thornbill. © 2006 Nevil Lazarus.

It all comes down to experience and observation, meaning that you have to take whatever opportunities you can to observe these two species side by side.

The problem here is that Brown Thornbills are mid-storey/shrub layer foragers and Striated Thornbills are canopy or treetop foragers. How do we get to compare the two when they live so far apart? Let’s face it, we so seldom get the chance to even find a Striated Thornbill as they’re so tiny and never come down from the tree tops.

Striated Thornbill. © 2007 Nevil Lazarus.

Separate species, separate lives

The answer can be found if we follow the lives of these tiny insectivorous birds. Brown Thornbills are monogamous pair breeders: a fairly unique arrangement among the cooperative breeding thornbill clade. This is why you seldom see Brown Thornbills in any more than pairs. Of course, around breeding season you will see them feeding their young, who will remain in their parent’s territory until they’re of an age when they can disperse, but this is not the norm.

A beautifully crafted Striated Thornbill's nest (note the nestling hiding in the entrance). © 2006 Ricki Coughlan. Press image to enlarge.

For Striated Thornbills it’s a very different story: these birds move around larger territories in extended family groups of around, and sometimes more than, 30 birds. When breeding season comes these tiny thornbills pair up and, in the company of a couple of younger “unmarried” birds, will construct a nest and raise their young cooperatively. By “cooperative” we mean that the “unmarried” birds – frequently the previous year’s offspring – assist the breeding pair in raising their offspring. Families build their nests in trees around 50 to 80 metres apart, depending upon the structure of the forest. If a family fails in its breeding attempt, it will join up with its neighbours and assist them with raising their family. When the entire process is complete, the super extended family joins together again and every member of the flock feeds any young which still might be begging for a morsel. The time of year when this takes place around Sydney is from mid August to late October.

Now’s the time to make comparisons

It’s of great use to little brown bird enthusiasts that breeding season is the time of year the Striated Thornbills greatly diversify in terms of where they forage. Right now you will find Striated Thornbills foraging among the understory shrubbery, mid-story and canopy layer, so it’s an excellent time to see these birds down low very frequently. This is a time when Brown and Striated Thornbills come into conflict and I’ll have more on this in a coming post. This also gives us the opportunity to make the comparisons which will help us to really improve our ID skills with these two species.

Like all of these things, it’s easy when you know how and you also know the pitfalls in identifying these birds. Let’s go through them . . .

Rules for observing Little Brown Birds

First up and most importantly: Don’t get fooled by the similarities. Most birders who struggle with little brown birds get caught up focussing on the similarities. Here, we’re going to learn about the immediately apparent differences which will aid identification. We’ll consider these in the light of some of the pitfalls which invariably crop up in the field.

The following two images aren’t meant to be works of art: they’re meant to clearly define the diagnostic features of these two species. To serve as an indicator of what to focus on in the field. If you look for these features when you see these birds, you’ll notice that they’re immediately obvious.

The Brown Thornbill with diagnostic features clearly defined. © 2009 Ricki Coughlan.

Striated Thornbill with diagnostic features clearly defined. © 2009 Ricki Coughlan.

1. Chest markings

Determine if your thornbill has striations or “arrow heads”. There are clear differences in the chest markings of Brown Thornbills and Striated Thornbills. The Brown Thornbill’s chest markings are clearly more like arrowheads in shape. The pitfall is wet birds. If a Striated Thornbill is damp from, getting about in wet foliage, its chest markings may appear to be more like arrowheads. If your bird is wet, move onto the next easy field marks . . .

2. Crown colouration

These two thornbill species are really easy to split by crown and facial plumage. The Brown Thornbill has a plain face and cap, with a buff-rufous frons (forehead). Its facial markings are fine and not so striking. The Striated Thornbill has an obvious tan-brown cap with tiny white striations through it. The dark striations on its face are more prominent.

3. General colouration

The Brown Thornbill is generally brown or greyish in overall appearance, whilst the Striated Thornbill has an obvious yellow tinge to its body. The pitfall can be poor lighting and if this is the case, move on to the next easy diagnostic feature . . .

4. Eye size and colour

The eye of the Brown Thornbill appears to be very large, whereas the eye size of the Striated Thornbill tends to appear to be of what we consider normal proportions. If light permits, you will note that the Brown Thornbill’s eye is red-brown and the Striated Thornbill’s eye is very dark or, in direct light, pale grey.

Sealing the ID – experience is the key

Generally the path to identification is to pick one of these features and then use a second one to make a positive identification. However you will note that these are all comparative features and that is the point of this post. You need to get experience comparing these two species side by side or at least see them both in the same morning’s birding. A few encounters with these delightful small birds will give you the opportunities to use the tools to put away your ID issues with both of them and enhance your day in the beautiful Sydney bush.

We’re going to be looking at the lives of these birds in greater detail over coming weeks: what they can tell us about the environment, how they contribute to healthy ecologies and they respond to changes which humans impose on their environment. They’re exciting stories which take us into the heart of what the study of birds is about, understanding what you’re looking at in the field or simply enjoying your birding more. They also help to inform us about improving the way we manage and relate to the environment. There’s really no end to the fascination out there for those who are fortunate enough to love birds and nature and these little brown birds are a great entrée to much of this.

Until next time . . . Happy Birding!

Crested Terns are gorgeous on the wing, with powerful flight and brilliant soaring ability: true masters of flight. When they dive on their prey in the water, their wings-back plunges are eye-rivetting. Five races of Crested Tern are found across the Indo-Pacific region. The race we have in Australia are Thalasseus bergii cristata and, numbering up to 500,000 birds, it is the most numerous.

A dapper pair prepare for display at Boat Harbour. © 2009 Ricki Coughlan

Banded terns on Sydney headlands

MERRIES REEF at Boat Harbour always has at least a few Crested Terns roosting among various cormorant species, Silver Gulls, Kelp Gulls and a variety of migratory shorebirds. In almost three years of weekly surveys I have only observed three or four Crested Terns wearing numbered aluminium leg bands – one of them an anodised orange band.

On last Wednesday’s high tide count I recorded a roost of 827 Crested Terns on the reef. Of these, 22 birds had numbered aluminium leg bands, one had an orange anodised leg band and another with a green anodised leg band. Clearly, something unusual is going on!

Visitors from Victoria

I contacted Clive Minton, who handles the record keeping of banded shorebirds (which includes gulls and terns) in this part of the East Asian-Australasian Flyway and was informed that the terns with the coloured bands were banded as chicks on Mud Island, Victoria, around 743 kilometres from Sydney, but considerably further if we accept that these birds have flown along the coast. The bird with the orange band was banded in 1995 and the tern with the green band was banded in 1998. I think that under the circumstances, we can also accept that the remainder of the terns with plain aluminium bands were also banded in Victoria.

A Crested Tern on Boat Harbour with orange anodised leg band. © 2009 Ricki Coughlan.

Last Saturday at Long Reef we counted 40 Crested Terns among a roost of cormorants and Silver Gulls. Three of these birds also had leg bands. We have recorded Caspian Terns on the reef which were wearing leg bands, but never any Crested Terns with leg bands.

A Crested Tern on Boat Harbour with green leg band. © 2009 Ricki Coughlan.

Breeding? Fishing? Both? or . . . something unknown?

So what is happening? There is little doubt that we are experiencing an influx of Crested Terns from Victoria and given the large numbers of these birds in breeding plumage and courting at present might mean that these birds have come north to breed.

Another event currently taking place just off the coast may also have a bearing on the arrival of these terns. For the second year running, a large mass of warm water has extended southward from Queensland and is currently extending just south of Sydney, around a kilometer off the coast. This southern movement of the warmer water will effect the patterns of movements of large numbers of fish: species which prefer colder water will be forced further out to sea and closer to the coast. There would be a southward movement of fish which prefer warmer water. They’ll be tracking the warmer current. It may well be that these terns are taking advantage of this shift in the dynamics of ocean currents and are simply following the patterns of movement among those fish species upon which they prey.

According to Clive Minton, these birds have been breeding further north, probably on islands and sandbars off the coast of Queensland. What we are currently seeing on our rocky headlands are birds which are now making their way south towards Victoria again. It may be that, unlike most years when it is not present, the extant body of warm water off the coast is providing them with a food resource of such excellence that the terns are not in any hurry to return to Victoria. These birds were banded with a different colour each year as part of a study aimed at determining the age at which Crested Terns commenced breeding.

Report flagged and banded birds

WHATEVER THE REASON your birds are about, it’s a good reminder to keep your eyes out for leg bands or leg flags on birds, because the more data we have, the more questions we can ask, ultimately leading to more answers and more conservation opportunities. Remember to report your sightings to mintons@ozemail.com.au or visit the Australasian Wader Studies Group sightings page.

Until next time . . . happy birding!

Note the rufous plumage around the neck of the stint on the left. This becomes extremely vibrant when the sun hits it directly. Press image to enlarge. © 2009 Ricki Coughlan.

The second year Red-necked Stint with more than a little adult plumage has successfully survived all that a Sydney winter can throw at a rocky headland (which is a bit like being flogged with a wet lettuce leaf – you’ll know what I mean if you’ve lived in Sydney this winter!). To read more about this bird visit the June 29 post.

However, I find this interesting enough to at least publish another image of this bird which offers a nice comparison with another juvenile Red-necked Stint which is more in line with the norms for this species.

This bird will soon be lost in the masses of stints returning from the northern hemisphere in coming weeks.

I’ve had to abandon the Ruddy Turnstone limpet predation survey for the winter, as there are so few juvenile turnstones on the reef this year that the sample is statistically way too small to be of any use (check out the “Ruddy Turnstone study” category in the sidebar). The project is almost at an end, with enough data to start moving things towards the laboratory, so it’s a disappointment that we wont be able to capture some juv – adult comparisons to determine if the rejection of siphonaria limpets has any basis in age cohorts. I was pondering this yesterday whilst observing a lone Ruddy Turnstone amid a foraging party of 20 Red-necked Stints and a couple of Double-banded Plovers, when some Sooty Oystercatchers landed not too distant from me.

A small portion of an oystercatcher's feast. The arrow points to a rejected siphonaria limpet amid the predated cellana limpets. A couple of the limpets bare the hallmarks of this oystercatcher's foraging guild: a "hammerer". © 2009 Ricki Coughlan.

I GAVE the oystercatchers a bit of time to settle and then strolled across the reef and began to observe their foraging. What unfolded in the next half hour has added considerable interest to my work on limpet predation on Long Reef. The oystercatchers were taking a large number of Cellana tramoserica limpets: nothing unusual about that. What was unusual was that the limpets they were feasting on were much smaller than usual and they were also sampling – and rejecting – Siphonaria furniculata limpets. There was not just a few either: after 5 minutes of observing, I moved in and counted 34 rejected siphonaria limpets and 16 predated cellana limpets in a 5 square metre area. Up until now, I have not observed Sooty Oystercatchers rejecting siphonaria limpets, as they generally take limpets which are larger than the average siphonarias and I have presumed that the siphonaria limpets have not been targeted as they’re smaller than their usually predated limpets.

A Sooty Oystercatcher on Long Reef with a cellana limpet of the size which we are generally accustomed to seeing this species take. © 2009 Ricki Coughlan.

DETECTIVE WORK in nature requires great diligence, finding all the tiny puzzle pieces and building a picture which works. What I now have is evidence that turnstones are not alone in their rejection of siphonaria limpets – further pointing to foul taste, foul odour or toxicity (or all three). I’m pretty certain now that we can rule out that the flesh is too difficult to remove from the shell as a reason for rejection, as surely there’s no way that these masters of muscle removal would be thwarted by a mere siphonaria. Although we don’t have statistical data on siphonaria limpet rejection by age cohort, we can probably rule out inexperience as a factor in flipping the siphonaria limpets in the first place as it goes across species and my oystercatchers were adult birds.

I’m now certain that all will be revealed when we get some samples of cellana limpets and both species of siphonaria limpets (S. furniculata & S. denticulata) into the laboratory for analysis.

As I strolled back up the steep hillside overlooking Long Reef I couldn’t help but wonder at the massive numbers of siphonaria limpets which are flipped and left to die each day and, indeed, the massive numbers of cellana limpets which are gorged upon by the turnstones and the oystercatchers. The rate of recruitment, of replenishment, must be enormous, further pointing to the extraordinary vibrancy of habitats like these and the need for us all to ensure that they remain inviolate, in order for the fantastic play of life to continue to unfold in this little spark of magic on Sydney’s coast line.

Until next time . . . Happy birding!

A Little Penguin on Long Reef. © 2006 Ricki Coughlan.

This is seven Little Penguins too many. These events highlight a convergence of problems that we have on the Northern Beaches, and across Sydney generally: a failure of  some dog owners to recognise their responsibilities and a failure on the part of Local Government to enforce the NSW Companion Animals Act and local By-Laws of their own making. In between these two problems are the environment and the dogs.

The relevant parts of the Act are:

1. Dogs must be under the control of their owner at all times
2. Dogs must be on a leash in a public place
3. Dogs are only permitted off leash in their owner’s properties or where signs specify “off leash” areas
4. Dogs are not permitted on beaches such as we have around Sydney, on or off the leash
5. Properties where dogs are housed must be secure enough that the dogs cannot escape.

Get a copy of the Act

YOU CAN download a copy of the NSW Companion Animals Act here, or an extract of the relevant sections here.

Why is any of this too hard? Why do people take on the care of a dog and then childishly fail to comply with the laws or try to pressure to change them at the expense of community standards and the environment? I hear lots of talk about rights, but where is the talk about responsibilities? It’s childish to think that you have rights without responsibilities and it’s time that all dog owners (and cat owners) faced up to this fact.

The Manly rookery is the only mainland Little Penguin rookery in NSW and despite fantastic stewardship on the part of the Wardens at Manly, the Local Council seems unwilling to live up to its responsibilities too. The Wardens there report many incidents of abuse by dog owners who are determined to do the wrong thing but where are the Council Rangers (Correct. Putting parking tickets on cars).

Dog (owner) disturbance elsewhere on the Northern Beaches

MANLY IS NOT the only site on the Northern Beaches where errant dog owners are abusing the privilege of having a dog in their care. Anybody who enters any Reserve on the Northern Beaches on a Sunday morning, Long Reef at any low tide and Careel Bay at any low tide will be able to confirm regular and blatant disregard of the law and what amounts to abuse of the environment. And don’t you dare point this out to these environmental vandals because you’ll become the victim of extremely vocal abuse and threatening behaviour every time. We should be aware that it’s not the dogs which are at fault here. They are merely being what they are and taking advantage of an opportunity for a romp and a chase.

Dog disturbance on Careel Bay. The victims in this instance were a pair of Masked Lapwing. © 2009 Ricki Coughlan.

A MAJOR FACTOR in the near total wipeout of migratory shorebirds at Careel Bay can be put down to the high level of disturbance at that site and the key disturbing factor are dogs which people insist on sending onto the mudflats for a run at low tide. This has nothing to do with claims of letting Fido out for a swim it is simple ignorance and abuse of the environment.

The same is true for Long Reef. Although the area is historically known to have held a Little Penguin rookery, the chances of re-establishing that rookery and taking pressure off the  Pittwater rookery, which is somewhat overcrowded, is virtually nil. Rats and foxes are problematical at this site but the chief disturbing factor is once again irresponsible dog owners who think that they’re above the law and the dog, which nobody forced them to take into ownership, has “rights” which transcend all community standards and the needs of the environment.

Clearly threatened and incensed at being photographed doing the wrong thing, this dog walker is coming over to abuse me. In another breach of the Companion Animals Act his dog is adopting a threatening posture too and he's doing nothing about it. © 2009 Ricki Coughlan.

It’s not my dog

I’M ALWAYS HEARING dog owners tell me that their dog doesn’t chase birds or bandicoots or wallabies. Indeed not one dog owner has ever admitted this to me. However, it’s somebody’s dogs that I have seen chasing Black Wallabies through Irrawong Reserve on two occasions. It’s somebody’s dog who I have rescued a Little Penguin from on Long Reef. It’s somebody’s dogs who I have witnessed chasing birds almost every time I have visited Careel Bay. It’s somebody’s dogs that I have witnessed chase Sooty Oystercatchers at Long Reef on more than one occasion. Of course it’s not every dog but sadly laws are not made for those with common sense or a sense of fairness and decency, they’re made to protect the interests of the majority against the folly of the errant minority.

Questions for Local Government

My Little Penguin rescue. Long Reef 2006. © 2006 Ricki Coughlan. Press to enlarge.

MY QUESTIONS to Local Governments on the Northern Beaches are:

Why isn’t it compulsory that all residents who register a dog in this area must first read and sign off on the NSW Companion Animals Act?

Why are all your energies going into booking people who overstay at parking metres and no energy ever going into protecting our envionment and enforcing compliance with the NSW Companion Animals Act, your own By-Laws and other laws regarding State Parks and Reserves?

The answer wouldn’t be politics would it? It wouldn’t be that you’re putting political expediency above your obligations to protect the local environment?

Time for a resolution

BEFORE DOG OWNERS get their hackles up, I happen to be someone who loves dogs. These gorgeous, highly social and intelligent animals bring alot of pleasure into the lives of many people, including mine, and clearly somewhat enjoy their own lives too! I also recognise that even the most errant of dog owners appear to enjoy our Reserves: otherwise they wouldn’t be walking their dogs through them. But their values are skewed towards their one individual animal against the well being of entire “island” reserves: the only homes left in the region for our beleaguered wildlife. To say that walking a dog through a reserve or permitting it to chase birds is not harmful to the environment is to reveal your ignorance of ecology, animal behaviour and the science which backs up the concerns of conservationists in this regard.

I would like to propose that Local Governments convene a forum on the Northern Beaches where the needs of dogs in the community are firmly established and that these needs be met. I think that we should find more places where dogs can be off leash and that the amenity of these places be brought up to scratch so that they are pleasant places to be for humans as well as dogs. I would also like to see a trial conducted at one or two out of the way beaches where people can take their dogs to swim. Permanency could be contingent on how well dog owners clean up after their dogs and control them to and from the beach. On the other hand I would like to see larger fines and more stringent enforcement on our reserves and environmentally sensitive locations. What could be fairer than this?

With good will, truthfulness and respect from all parties, we can come to a workable solution which will keep everyone happy. We need to go in that direction because what we have at the moment is entirely unacceptable for the environment and the dogs.

Until next time . . . Happy Birding!