A review by Dickermann 1988 lists 6 subspecies of Chordeiles pusillus, and 3 of these would occur in NE Brazil:
novaesi, in Piauí and Maranhão;
xerophilus, in Paraíba;
pusillus, in Bahia, Goias.
In the same review, Dickermann also suggested that two specimens from Ceará could possibly belong to a further subspecies, yet to be described.RPPN Mãe-da-lua.
Figure 1. I inadvertently flushed this bird from its daytime roost on the stony ground of a hill with sparse vegetation and scattered rocks, in an area of secondary Cerrado. I watched it flying around and then landing not too far away on a similar patch of stony ground. The camouflage of the plumage is very efficient, and I would not have found the bird again, if I had not seen where it landed.
Identification as Chordeiles pusillus was partly based on its appearance in flight (after flushing, no photo), when it showed a thin, but distinct white band along the posterior margin of the otherwise dark wings. This band is formed by the white tips of the secondary flight feathers, and can be quite striking (Sick 1997, Gwynne et al. 2010).
I did not hear this nightjar vocalizing on the day I made the photo, but a few weeks later, during dawn, I recorded songs and calls of Least Nighthawks in the vicinity.To top of page
Figure 2. Details of the bird from fig. 1.
Just behind the bend of the wing, this nighthawk has a conspicuously coloured area: dorsally blackish and brownish (label A), and ventrally and posteriorly mostly rufous (labels B). The anatomical designation of this section of the plumage is "dorsal part of the small and median secondary wing-coverts", or something equivalent (Juana 1992, Clark 1993, Sick 1997).
The drawings available in the literature do not show this area behind the wing-bend in the same colors. In Fig. 3 in Cleere 1999, it is plain rufous. Fig. 2 in Mata et al. 2006, p. 253, and the figure in Gwynne et al. 2010, p. 137, do not show any distinct coloring of this section at all.
On the other hand, on a photo by Mauricio Mercadante in the wikiaves website, the wing-bend area is similar.
I suppose that the discrepancy between the photos shown here, and the figures in the literature, can be explained by differences between subspecies, between reproductive and basic plumage, and so on. But at present, there is not enough detailed information about Chordeiles pusillus available, to definitely confirm this.To top of page
Figure 3. This photo is probably from the same individual as those above. The image is blurred, but it is still possible to see the barred underparts of the bird, a detail not visible in figures 1 and 2.To top of page