Ian’s Bird of the Week – Hoary-headed Grebe ~ by Ian Montgomery
Newsletter – 6/17/13
The Birdsville Track isn’t famous for its waterbirds but when we drove along it in April there had been recent rains and we were in for a few surprises. Not, happily, of the getting bogged variety, but birding ones at several spots including this one where we camped more or less in the middle of nowhere beside a small dam. That speck on the left hand side near the lone tree is my car.
As well as some Pink-eared Ducks, there were several Hoary-headed Grebes. The ones in the first and second Grebe photos are in non-breeding or immature plumage and, although they are larger than Australasian (Little) Grebes (30cm/12in versus 25cm/10in in length) you need to use subtle field marks to distinguish them in these plumages.
The main field marks are: the Hoary-Headed has greyish rather than rufous-tinged flanks and whiter breast (though the bird in the first Grebe photo shows that you need to be careful with stained plumage); the border between the dark cap and pale cheeks goes below rather than through the eye in the Hoary-headed Grebe and the eyes are different in colour and pattern. The Australasian Grebe has conventional-looking eyes with yellow iris while the Hoary-headed Grebe has button-like eyes with a dark iris with a white inner and a white outer ring. This is probably easier to see in the closer bird in the second Grebe photo.
It’s only when you see a bird in breeding plumage with spiky pale head feathers that you understand where it gets its unusual English name (the scientific name Poliocephalus means a much more prosaic ‘grey-headed’). ‘Hoary’ literally just means ‘whitish’ but it’s an adjective that is usually applied to frost and snow so it is used as a metaphor for ‘frosty’ in the English names of 4 or 5 bird species globally. (Another example is the Hoary or Arctic Redpoll http://www.birdway.com.au/fringillidae/hoary_redpoll/index.htm which fits better geographically.) We encountered the bird in breeding plumage about a week later at Bowra Station near Cunnamulla, SW Queensland, where we spent a few nights on the way back to Townsville.
Grebes are almost exclusively aquatic and expert divers. Their legs are set far back on the body, so they are very awkward on land which they avoid as much as possible. They build floating nests out of water plants so they just need to haul themselves out of the water to tend the eggs and the young leave the nest soon after hatching. They usually dive rather than fly to avoid predators, though they can fly long distances if necessary to find water and the Hoary-headed Grebe, commonest in southern Australia is rather a nomad in the north. It’s closest relative is the New Zealand Grebe or ‘Dabchick’ and is the only member of the genus Poliocephalus.
Ian Montgomery, Birdway Pty Ltd,
454 Forestry Road, Bluewater, Qld 4818
Tel 0411 602 737 firstname.lastname@example.org
Bird Photos http://www.birdway.com.au/
Recorder Society http://www.nqrs.org.au
Looks like quite a deserted place, but those are cute little Grebes. I am glad Ian gets out and about so much there in Australia. He always finds something interesting for us to learn about. Thanks, Ian, for sharing.
I will open rivers on the bare heights, and fountains in the midst of the valleys; I will make the wilderness a pool of water, and the dry land springs of water. (Isaiah 41:18 AMP)
The Hoary-headed Grebe (Poliocephalus poliocephalus) is a member of the grebe family found in Australia and New Zealand. The bird takes its name from the silvery-white streaking on its black head. It is common in Australia, with a population of about 500,000. Its habitat is similar to that of the Australasian Grebe.
The Hoary-headed Grebe feeds on aquatic arthropods, mostly caught by deep diving. This species feeds during the day, and when the light is poor, forages mostly at the water surface.
Hoary-headed Grebes breed from August to January. The nests are a floating platform of water weeds, similar to that of the Australasian Grebe, and usually some distance out from shore among sparse reeds or other plants, anchored to and at least partly supported by them. A shallow depression on top is just slightly above water, so the eggs are lying in water or dampness. The eggs are concealed under pieces of wet vegetation when the incubating parent leaves so that the nest appears empty. Under full sun the covered eggs are warm and moist, often left unattended for some time. The egg’s appearance is oval, white, and soon stained brownish ochre, while the clutch is usually 2–5 eggs. Incubation is 20–24 days and egg size is 39 x 27 mm. (Wikipedia with editing)
Hoary-headed Grebe – Wikipedia