23 March 2012

More photos on Flickr

Created a new set on birds photographed in Canada on my Flickr account (to view click here). More to be added shortly.

20 March 2012

The notorious tapaculo

In 2007, Mouse-coloured Tapaculo S. speluncae, a species found in the mountains of the Atlantic Forest in South America, was split by the Brazilian Committee of Ornithological Records (CBRO) and renamed Serra do Mar Tapaculo Scytalopus notorius (after the Serra do Mar mountains of the region). Birders everywhere (okay, birders in Brazil) were just starting to get used to the new name when the CBRO suddenly, and mysteriously, reversed their decision!

The Scytalopus genus of tapaculos are arguably the most taxonomically complex passerines in Latin America. Typical tapaculos, they are extremely difficult to see which makes them very tricky to study. In fact, they appear to like nothing more than remaining hidden from frustrated birders by creeping around mouse-like in dense vegetation, while monotonously calling their heads off! But over the last few decades new populations have been discovered and the genus has seen enormous taxonomic changes, with around 40 species now recognised compared to just 11 in 19703. Associated with mountains, most are found in the Andes but some are restricted to south-east South America where six species are now recognised, three of which have been described since 2005!

The specific name of Mouse-coloured Tapaculo - speluncae - has long been the subject of intense taxonomic debate, with ornithologists divided over whether this is the same species originally described and given this name. The answer not only has significant implications for the nomenclature of Mouse-coloured Tapaculo, but also for other Scytalopus species recently discovered in south-east Brazil.

What's in a name? The nomenclature of Mouse-coloured Tapaculo Scytalopus
speluncae has long been a topic of intense debate, with ornithologists divided over
whether this is the same species described and attributed the specific name
speluncae by Édouard Ménétriés in 1835. This male at Pico da Caledônia, Rio de
Janeiro state, Brazil, in October 2007, was laughing so uncontrollably at our efforts
to work it out, that it momentarily forgot that it was supposed to be skulking around
in dense vegetation annoying birders and allowed itself to be photographed out in
the open for a change.

In 1835, French zoologist, Édouard Ménétriés, collected and described the first Scytalopus tapaculo in the region - an adult male collected in the Espinhaço mountains in Minas Gerias state, near the town of São João del Rei, that he named Malacorhynchus speluncae (placed in the genus Scytalopus today). Ménétriés described it as uniform mouse grey above, slightly paler grey below and becoming whitish towards the middle of the breast and on the throat (illustration of type specimen below). Subsequently, similar, albeit darker birds were discovered in the Atlantic Forest mountains in Rio de Janeiro state, a long way from the Espinhaço mountains, and identified by ornithologists Hellmayr (1907) and Ihering & Ihering (1907) as belonging to the same species (know today as Mouse-coloured Tapaculo).

Surprisingly, no other Scytalopus tapaculos were subsequently found in the São João del Rei region and so ornithologists questioned São João del Rei as the type locality of Ménétriés specimen3 (a notion given credence after the type localities of other specimens collected by Ménétriés were found to be erroneous), suggesting it was actually collected in the Atlantic Forest.

Illustration of the S. speluncae type specimen described by
Ménétriés in 1835. Note the whitish throat, grey flanks with no
buff and pale legs. (Édouard Ménétriés)

Then in the 1990s, not one but two forms of Scytalopus tapaculo were discovered hiding out in the Espinhaço mountains - one in the northern part of the range (described in 2005 as Diamantina Tapaculo S. diamantinensis), and the other in the south around São João del Rei! However, these São João del Rei birds are quite different, morphologically and vocally, to the Atlantic Forest taxon, being paler grey, noticeably whitish on the central belly and most significantly, buff with dark barring on the flanks, rump and under tail coverts (photo here)3. They were clearly a different species, and so which species had Ménétriés described? Was it the São João del Rei species afterall, or a bird from the Atlantic Forest as suggested? Whichever one it is must be attributed the name speluncae, and the other would need to be described as a new species.

Scytalopus tapaculo species discovered at São João del Rei,
the type locality of S. speluncae described by Ménétriés.
Note the obvious buff barred flanks and rump, medium grey
underparts and pale legs. (Vitor Torga Lombardi)

A study by Raposo et al. published in 2006, re-examined Ménétriés's type specimen and compared it with new topotypes collected from São João del Rei, as well as specimens from the Atlantic Forest. Although the specimen is damaged, they found a few buff feathers on the rump and flanks of the type specimen (not mentioned by Ménétriés) and argue that these, together with the whitish central belly and throat and paler mid-grey colouration, are all features not found on the Atlantic Forest birds3 (especially adult males1). Therefore, Ménétriés's type specimen must be from São João del Rei, and so the name speluncae must be applied to this form and Mouse-coloured Tapaculo must be described as a new species, for which they proposed the name Serra do Mar Tapaculo Scytalopus notorius (notorius because of the controversy surrounding the species).

The following year, this proposal was adopted by the CBRO and the issue seemed to be settled, but then three years later a similar study by Maurício et al.1 concluded completely the opposite! They point out that the plumage of adult male Mouse-coloured Tapaculo actually varies considerably - ranging from homogeneous blackish grey with no traces of any buff feathers (as put foward by Raposo et al.), to mid-grey with some buff barred feathers on the flanks and rump (a feature shown by about 25% of adult males). In contrast, the São João del Rei taxon exhibits a very clearly marked plumage pattern (see above), being dark grey above and paler grey below a whitish center to the belly and obvious buff barred flanks, vent, under tail coverts and rump. They showed that the buff feathers on Ménétriés type specimen are nowhere near extensive enough for it to be the São João del Rei species, and also the central belly on the type is actually medium grey and not white. However, the plumage of Ménétriés type falls well within the variation found within Mouse-coloured Tapaculo, and therefore the Atlantic Forest species must retain the name speluncae.

In the end, Maurício et al. won the support of the South American Classification Committee and the CBRO reinstated Mouse-coloured Tapaculo as the name of the Atlantic Forest species. With this issue finally laid to rest, the São João del Rei species could be formally described, and in 2010 was announced as a new species - Rock Tapaculo S. petrophilus.4

Adult male Mouse-coloured Tapaculo Scytalopus speluncae, Pico da Caledônia,
Rio de Janeiro state, Brazil, October 2007. Same bird looking less smug now that
ornithologists have finally worked out what it is! Endemic to the mountains of the
Atlantic Forest, this is the darkest and most uniform in plumage of it's genus in
south-east Brazil, but they are variable, with the male sometimes showing some
buff on the flanks or rump. Note the dark grey plumage, very slightly paler throat,
lack of white on the underparts and dark legs and bill.

References

1 Maurício, G.N., Bornschein, M.R., Vasconcelos, M.F., Whitney, J.F., Pacheco, J.F. & Silveira, L.F. (2010) Taxonomy of "Mouse-colored Tapaculos". I. On the application of the name Malacorhynchus speluncae Ménétriés, 1835 (Aves: Passeriformes: Rhinocryptidae). Zootaxa 2518: 32–48.
2 Raposo, M.A. & Kirwan, G.M. (2008) The Brazilian species complex Scytalopus speluncae: how many times can a holotype be overlooked? Revista Brasileira de Ornitologia 16(1): 78–81.
3 Raposo, M.A., Stopiglia, R., Loskot, V. & Kirwan, G.M. (2006) The correct use of the name Scytalopus speluncae (Ménétriés, 1835), and the description of a new species of Brazilian tapaculo (Aves: Passeriformes: Rhinocryptidae). Zootaxa 1271: 37–56.
4 Whitney, B.M., Marcelo, F.V., Silveira, L.F. & Pacheco, J.F. (2010) Scytalopus petrophilus (Rock Tapaculo): a new species from Minas Gerias, Brazil. Revista Brasileira de Ornitologia 18(2): 73-88.

16 March 2012

First spring migrants

It really didn't feel very spring-like in the dull cold conditions at Staines Moor early this morning, and a pair of Goosander on the Colne, 1 Water Pipit, 1+ Common Snipe, 60 Fieldfare, 5 Redwing and 5 Teal all added to the winter chill. But make no mistake, spring is definitely springing!

3 distant Sand Martins headed over west first thing, and a scan across the anthills revealed a male and a female Northern Wheatear hopping around together in the north-east corner of the moor (I've not heard of any females seen so far this year. Is this the first?). I absolutely adore Wheatears and these two birds really made my day! 3 Chiffchaff (2 heard), 1 Common Buzzard W and 2+ Redshank completed the day's passage migrants, but the moor is now alive with singing and displaying local breeders including 13 Lapwing, 9 Reed Bunting and lots of Skylark and Meadow Pipits.

Also seen were 1 Little Egret, 2 Little Grebe and 2 Egyptian Geese on the Colne, 4 Canada Geese over (a good patch bird, yes really!) and a Pheasant, and on adjacent Stanwell Moor 2 more Chiffchaff, 4 Shelduck over and 2 more Pied Wagtail.