Band-winged Nightjar is a widespread species of South American Caprimgulgid found throughout the Andes, in Patagonia, eastern Brazil, and the Tepui region. As of the most recent (2010) edition of the Clements checklist it is comprised of seven subspecies:
- longirostris of Eastern Brazil and northeastern Argentina
- ruficervix of the northern Andes from Venezuela south through northern Peru north of the Maranon
- atripunctatus of the Andes from Peru south of the Maranon through northern Chile and Argentina
- bifasciatus of central Chile and western Argentina
- patagonicus of central and southern Argentina
- roraimae of the Tepuis
- decussatus of coastal Peru and northern Chile
Of these seven subspecies, xeno-canto has representative recordings of six of them. Only patagonicus is absent. The song of most of the subspecies is a high-pitched whistle, with tonal quality and patter variable among the subspecies. The length of each whistle is typically between .55 and .8 seconds, and I won’t go into note length except where it differs from this range.
A browsing of xeno-canto’s recordings of Band-winged Nightjar will show some significant variation in the songs of the species. This article doesn’t deal with the calls of Band-winged Nightjar at all, mostly because the sample size is far too small to analyze them.
C. l. longirostris
The nominate subspecies, found in eastern Brazil, has a very high-pitched, clearly whistled song, with an underslurred pattern (that is it falls than rises in pitch). The frequency range is between 4.9 kHz to 3.6 kHz in two of the recordings on XC, and 4.6 kHz and 3.1 kHz in the other. This subspecies has by far the most clearly ascending element after the initial downslur.
C. l. ruficervix
This subspecies of Band-winged Nightjar is the most well represented on xeno-canto. It’s song consists of a very high pitched clear whistle, in most examples initially even in pitch before descending; in a couple more evenly descending. The frequency range of this form falls between 5.3 and 6 kHz on the upper and end and 3.8 kHz on the lower end, thus consistently higher pitched than longirostris. It also differs from that form in lacking the noticeable upslur at the end of the song.
C. l. atripunctatus
After ruficervix this is the most well represented subspecies on XC. It’s song is fairly similar to that of ruficervix in that it starts out as a high-pitched, fairly even whistle followed by a descending whistle, but differs in that the overall tone of the whistle is distinctly burry, and that the end of the song evens out more than it does in ruficervix. Some of the examples end in an even whistle, while others have a very brief (barely noticeable) upslur at the end. In frequency it ranges from 4.9-5.3 kHz at the peak frequency to 3.6-3.8 kHz at the lower end. In this it is between longirostris and ruficervix in frequency.
C. l. bifasciatus
Bifasciatus sounds most like atripunctatus; the main difference is that (in the two examples on XC) it’s song starts out more strongly downslurred, and the slight upslur at the end is more noticeable. Structurally, the two examples of this subspecies on XC also have a more clearly whistled first half of the song, as opposed to the evenly burry songs of atripunctatus; this difference is audible if one pays attention for it, and in the small sample size available seems quite distinctive. The frequency in this subspecies ranges from 4.9 kHz at the top end to 2.6-2.9 kHz at the lower end; it is thus also distinctly lower pitched than atripunctatus.
C. l. roraimae
This isolated subspecies has a song quite different from all other subspecies of Band-winged Nightjar. In the one recording I’ve been able to find it’s song starts out very slightly ascending then evens out into a clear, high-pitched whistle. Unlike all other subspecies of Band-winged Nightjar there is very little pitch change. The frequency of the song starts out at 3.9 kHz and evens out at 4.3 kHz.
C. l. decussatus
The most divergent of the Band-winged Nightjar subspecies, vocally at least, is this form found in the lowlands of Peru and Chile. From the one example available on XC it’s song is utterly unlike that of any other subspecies, and why it continues to be considered the same species is beyond me. It’s song is much shorter (.35s) than any of the other subspecies, and is an overslurred (slurs up then down), burry note. The frequency ranges from 2.3 kHz to 3.3kHz, and is thus lower pitched than any other subspecies as well.
The range of vocal variation in Band-winged Nightjar, which appears to be correlated to subspecies and be readily diagnosable in all of them, is worthy of more research. In particular I would like to know what the patagonicus subspecies sounds like, and if there is any intermediacy between ruficervix and atripunctatus, and bifasciatus and atripunctatus. This vocal and geographical distinctness of longirostris, roraimae, and, especially, decassatus is just begging to be looked into.