Possible White-browed/Masked woodswallow hybrid

To: Nathan <>
Subject: Possible White-browed/Masked woodswallow hybrid
From: Vivien Rolland <>
Date: Thu, 17 Oct 2013 19:17:58 +1100
Hi Nathan,

Thank you so much for posting your message and these references -  they are 
quite interesting indeed!

I had a look at the part of "Boom and Bust" by Libby Robin, Robert Heinsohn and 
Leo Joseph which deals with White-Browed and Masked Woodswallows.
I cite page 212 and 213: "Hybridisation, however, has been rarely reported 
either by direct observation of mixed pairs at nests or from possible hybrid 
specimens in museum collections. On balance the evidence that they hybridise is 
tenuous although some low frequency of hybridisation cannot be ruled out. Even 
more remarkably, in a survey of ecological differences among closely related 
pairs of bird species in south-eastern Australia, these were the only two that 
could not be separated at all. And finally, their vocalisations are also 
essentially indistinguishable. This almost certainly is a unique feature of 
this pair of birds. I know of no reference to any other pair of bird species as 
different in appearance as these two are for which it is so hard if not 
impossible to distinguish vocalisations."


On 16/10/2013, at 10:14 PM, Nathan <> wrote:

> It seems that in this case HANZAB hasn't really looked as deep as possible, 
> the Handbook of Avian Hybrids of the World (cite) lists the two as "CAONHR 
> [Captive and ongoing natural hybridization reported]", however the only notes 
> that are added on its appearance were: "One reported hybrid looked exactly 
> like a Masked Wood-swallow, except it had a broad white eyebrow."
> The references it cites are:
>  - Avicultural Magazine 1964 (p. 188),
>                        ---------- 1965 (pp. 116–117)
>  - Barnard, H. G. 1944. Hybrid Wood-Swallows. The Emu, 44: 154;
>  - Boehm, E. F. 1974. Hybridism in wood-swallows. South Australian 
> Ornithologist, 26; 167;
>  - McGill, A. R. 1944. Hybridism in wood-swallows.The Emu, 44: 153–154;
>  - North, A. J. 1909a. Hybrid Wood-Swallow. The Emu, 8: 224,
>           ---------1909b. [On a hybrid Wood-Swallow]. Proceedings of the 
> Linnean Society of New South Wales, 33: 735.
>  - Sharland, M. 1972. The lure of wood-swallows. Australian Bird Watcher, 4: 
> 213–219.
> The two 1944 Emu notes are available at 
> McGill, as previously mentioned, refers to a diary kept regarding a mated 
> pair, along with a 1909 reference to North's writing in Emu and the Linnean 
> Society of NSW. The article describes this bird's appearance as: "It 
> resembles A. superciliosus on the upper parts, has the forehead, lores, 
> cheeks, ear coverts, and throat black, passing into blackish-grey on the 
> fore-neck; remainder of under surfaces ashy-grey with slight vinous wash; 
> under tail coverts pale ashy-grey; over and behind the eye a distinct white 
> eyebrow, but not extending so far onto the side of the crown as in A. 
> superciliosus." which sounds a lot like a slightly less extreme version of 
> Graeme Chapman's photograph.
> PDF copies of these articles are available at 
> (Notes and Notices) and
> though the descriptions are 
> identical.
> I cannot find an online copy of the Avicultural Magazine, though if you have 
> a spare $9,000 it seems like an interesting buy from Andrew Isles.
> Boehm says "A hybrid Wood-Swallow which strongly resembled a male A. 
> superciliosus but without the eyebrow, and having a black mask like A. 
> personatus was mist-netted, banded, and weighed east of Sutherlands, S.A., on 
> 8 Oct., 1972. The mask was margined with rufous instead of the usual white 
> margin. Weight of the bird was 38 grammes." This article in full is available 
> from 
> Finally, since the merging of BOCA and Birds Austrlalia I have been unable to 
> find or access the archives of Australian Field Ornithology (previously the 
> Australian Birdwatcher) so I cannot offer any insight into what Mr. Sharland 
> had to say.
> The upshot of all of this seems that hybrids between these birds have been 
> reported fairly often, a lot more than lots of species, however it is 
> surprising that there are so few offspring in the two species that are so 
> closely aligned in habits and habitats.
> ~Nathan Ruser


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