Butcherbirds

Adult male Pied Butcherbird - there is a reason for the glove, see below

Last weekend I was on a bird-banding trip to the Weddin Mountains, run by Richard Allen. There were seven of us altogether to set up and maintain vigilance over the numerous mist nets we had placed throughout a patch of wooded, partially-cleared pastureland adjacent to the nature reserve. Most of the birds in the area seemed to be local breeders, which was reflected by the catch of adult birds of a wide variety of species, but no high numbers of any one species other than White-plumed Honeyeater, which were abundant and breeding. One pair had a nest in the tree branches above the banding station. And we also found nests Spotted Pardalote, Speckled Warbler, White-winged Chough and Pied Currawong. 

The glossy black hood and wide white collar indicate that this is an adult male bird,
some of the bird's black feathers have faded to brown under almost
 a year of sunlight since it probably moulted and grew that set  

Butcherbirds are never abundant in any area as the pairs guard their territories well, excluding all others. So it was doubly opportunistic for us to catch two species, Pied Butcherbird Cracticus nigrogularis and Grey Butcherbird Cracticus torquatus. And as they were breeding, we had a chance to compare and note features of the two species' full adult plumage. The Pied Butcherbird illustrated here is an adult male, the distinguishing features for an adult being: the blue-grey bill with a black tip, juvenile and  immature birds have grey/brown bills through to dull blue, each with a dark grey tip; his hood is black rather than brown/grey of an immature bird. Adult females have less white on the outer wing coverts, less glossy black in the hood and grey on the back. 

Butcherbirds have a well defined hook on their bill tip

The Grey Butcherbird is very like the Pied and could perhaps be most quickly described as a similar bird, but of of duller plumage. As its name describes, it is grey overall. The adult male has a black hood, but white throat unlike the Pied's black bib. As with the Pieds, these adults also have blue bills with black tips, while the young birds have grey-brown ones with darker tips. The bird illustrated here is an adult female as she has a grey-brown hood and a distinct patch of off-white feathers in the lores, complete between the eye and bill; the male has a distinct white spot on the lores which does not extend to the eye.  

Adult female Grey Butcherbird

Great care should be taken when handling butcherbirds of any species as they can bite...

The hook on the tip of a butcherbird's bill is well adapted for gripping

Orchids

A cluster of Green-comb Spider Orchids

While mist-netting birds at the weekend, out at the Weddin Mountains, NSW, we found ourselves walking through  woodland understorey grassland, with numerous orchids in the sward. The first species I noticed was the Green-comb Spider Orchid Caladenia tentaculata which was growing in small groups of several flower spikes in several locations. All the flowers looked fresh and newly opened.  

A jewel in the grass

Other species which were frequent if not quite abundant included Purplish Bearded Orchid Calochilus robertsonii (Below), Blue Fingers Cyanicula caerulea, a species of greenhood and one or two species of sun orchid Thelymitra. I was too busy catching and banding birds to take enough photographs of all the species, so I grabbed what images I could on passing and sent them to Denis Wilson who kindly helped to identify them. He has some great illustrations on his own blog at  http://www.peonyden.blogspot.com.au/ .

A spectacular little flower

Buff-rumped Thornbill nest

A well hidden thornbill nest

The woods are busy with the sound of nesting birds at the moment. Some building, carrying material, some scolding in alarm as we pass by and others make almost constant contact calls between one another as they gather food for chicks. Chicks which lie still in hidden nests, but can blow their cover by emitting urgent begging calls as they see or hear their parents approach with food.

This nest is of a pair of Buff-rumped Thornbills  Acanthiza reguloides. It is a neatly crafted ball of bark strips and grasses locked together with spider webs and egg cases, then lined with what looked like a mix of small feathers, kangaroo hair and plant down. Set in a crack behind some flaking bark on an old Yellow Box tree it was invisible from most angles, except from that from where the side entrance could be discerned as a tell-tale round hole in an otherwise linear pattern of bark. 

I heard the adult birds first, calling to one another, then they gave alarm as I approached their nest tree. I could see they were carrying food; a large moth in the first case, the other something very small, so I walked back a few paces and watched the birds sneak into their nest to feed their chicks (3). They quickly set off for another foraging trip, and I knew I had about two minutes before they returned. So I unzipped the camera as I approached the tree, found the nest straight away, took a few shots, and walked away before the birds returned. Minimal disturbance, means minimal risk of predation by ravens or currawongs.

Small birds only need small niches to nest in - some very small

One Frogmouth less

The scattered feathers of a plucked Tawny Frogmouth

Today, while checking what used to be a Tawny Frogmouth territory, looking for this year's nest, I couldn't find anything. No nest, no birds. Then I found out why. There was a cluster of plucked feathers, from a Tawny Frogmouth, lying not far from the previous year's nest site. As the quills were all pulled out rather than snapped off, this is indicative of the bird having been killed and eaten by a raptor, most likely a Brown Goshawk as they nest a few hundred metres from the site. A mammal would have bitten off the feathers leaving cut shafts.

The kill was not recent, and as I could not find even a partially-built nest, I reckoned that the bird had been killed before the pair had began nesting. I still could not find the other bird of the pair, but it might have shifted a few hundred metres, and perhaps found a new mate and still be breeding. That will take another visit to check.

The complete shafts indicate that the feathers were plucked by a raptor.

Tree-creeper bill shape

Adult male White-throated Treecreeper

One of the advantages of mist-netting birds for banding is the opportunity to see them as we seldom have a chance to do so when they are flitting about the woodlands or wherever they live. While we were banding, aging, sexing and measuring this White-throated Treecreeper Cormobates leucophaeus during the same study as the previous blog article below, I noticed just how fine its bill was. There is a graceful curve when seen side on, but when viewed face-on, the bill can be seen to be remarkably tapered to a point. This is an adaptation for probing into cracks in tree bark, where they hunt for their food; tiny invertebrates.

The sleek lines of the treecreeper's bill - superbly adapted for reaching and grabbing tiny insects under bark

In comparison, other birds we caught that day included the Western Gerygone Gerygone fusca with a fine pencil-pointed bill for feeding on the tiniest of insects. Very fine, but straight and simple in line as it has no need for any further specialist shape like the treecreeper.

The tip of  this Western Gerygone's bill is polished by contact with the surfaces it has lifted insects from

There were also honeyeaters, which have slightly curved bills for probing into flower-heads to sup nectar, but their bills are mostly sturdy like that of this White-plumed Honeyeater Lichenostomus penicillatus as they also eat insects. The bill is very much thicker than that of the treecreeper.

The White-plumed Honeyeater has a slightly curved bill for accessing nectar in flower heads

And we caught a the generalist insect-eating Rufous Whistler Pachycephala rufiventris.  It has a broad, thick bill with a curved tip on the upper mandible, which enables it to catch insects on the ground or in the air and hold them firmly. Only when we held these birds successively in the hand did I appreciate just how finely tuned the treecreeper's bill is. Evolution is marvelous. 

An adult female Rufous Whistler: the hooked tip to its bill helps it hold prey tight