Tuesday, March 22, 2011

ID Feature: Dovetailing

Introducing a uniquely Western Australian birding challenge: the slightly obscure, but not entirely frivolous sport of differentiating Spotted and Laughing Doves solely by their tails!

While these species are usually easily separated by differences in size, colour, and neck markings, it is not uncommon to flush a dove and see only its rear end before it disappears. Furthermore, immature Spotted Doves are smaller, paler, and lack the black neck patch, so are less easily differentiated from Laughing on brief views.

A local Spotted Dove (Streptopelia chinensis) with plumage characteristics of the Indo-Malayan subspecies tigrina, including dark streaking on the wing feathers, light grey lesser coverts on the carpus, and off-white undertail coverts. Most Perth birds lack the latter two features. A CSIRO study [1] found that most Perth birds have dark streaking but browner wing and undertail coverts and are thus an ambiguous mixture of introduced subspecies tigrina and chinensis

Compared to the generally browner Spotted Dove, Laughing Doves (Streptopelia senegalensis) show rich coppery-pinks tones on the body, and more blueish slate-grey wings and rump

Although the only one of the major guides to do so, Pizzey [2] hints that the distinctive tail patterns are particularly useful in differentiating the two species:
Laughing Dove: "...outer tail feathers have much longer white tips than Spotted"
Spotted Dove: "...tail feathers mostly black, with broad white corners"
 However, careful observation reveals considerable variation in the tails of both species, as shown in the photo montages below.

Laughing Doves in flight - note the variable amount of white in the tail

Spotted Doves in flight - Spotted Doves fan their tails particularly broadly at take-off and landing

To summarise the key features, Laughing Doves can have a variable amount of white in the central tail, but consistently show:
- smaller black wedges, forming an arc high across the tail base
- longer white 'fingers' on the outer tail feathers, with much more white than black on the outermost feathers

By contrast, Spotted Dove tails show:
- thick black tail stripes, forming a 'V' towards the tail tip
- shorter white tips, equal to or smaller than the black base
- the outermost (lateral 3) feathers usually have white tips of equal size

When viewed from beneath (eg. in display flight), the tails of both species generally appear whiter, especially when backlit, but the differences in the extent and positioning of black patterning remain clear. Laughing Doves have clean white undertail coverts, while Spotted Doves in Perth are more likely to have dusky grey or brownish undertail coverts.

Happy dovetailing!  

Laughing Dove in flight. Note the small black wedges interrupted by white undertail coverts

[1] Frith H.J. & McKean J.L. (1975) Races of the introduced Spotted Turtledove, Streptopelia chinensis (Scopoli), in Australia. Australian Journal of Zoology 23, 295-306.
[2] Pizzey G. & Knight F. (2007) The Field Guide to Australian Birds 8th Edition. HarperCollins.

A burbling bevy of Laughing Doves

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