JAC: Matthew got really excited when he found out about a species of nightjar that was new to him, and the following post reflects his enthusiasm. It is a cool bird.
by Matthew Cobb
— Holly O´Donnell (@hollyodonnell00) October 30, 2015
Holly’s Tw*tter bio reads: “Conservation Biologist, Zoologist, working and studying in the remote Peruvian Amazon, previous Paraguay and Antarctica. Graduate of St Andrews University.” That’s quite a CV she has there!
Holly explained in another tw**t that she also caught the female partner of this lyre-tailed nightjar (no pic) – they had seen the pair flying together the night before.
The streamers are presumably used by females in sexual selection – there must be some link between their length and the male’s overall fitness. However, as with all such sexually-selected characters, there will come a point at which the fitness advantage that the male accrues via female mate preference is outweighed by the damage to his fitness (probably survival) caused by the sexual ornaments being too large. Without knowing anything about nightjar aerodynamics, these males look to be pretty much at the edge of what might be possible without losing the ability to fly so well.
Here’s some general biology from the Cornell neotropical birds site:
Lyre-tailed Nightjar (Uropsalis lyra) is unmistakable, with the males flaunting spectacular, pale-tipped tail streamers more than twice the bird’s body length. Uncommon and local in the Andes from Venezuela south to northwestern Argentina, this nightjar occupies gorges and most rocky cliffs, often near running water, at 2500-3000 m (and sometimes much lower). These birds roost on cliff faces and in caves, often concealed by hanging vegetation, using one roost for extended periods. Excluding the tail streamers, sexes are similar. A rufous collar extends across the nape, the scapulars are generally a pale, vermiculated gray, and the primaries solid black. Females are distinguished from female Swallow-tailed Nightjars (Uropsalis segmentata), which tend to be at higher elevations, by having a vermiculated black and gray crown (rather than a dark brown crown densely spotted with rufous) and a more prominent rufous nuchal collar. Male Lyre-tailed Nightjars forage and display nocturnally from the forest edge, with brief, fluttering sallies into the open, sometimes hovering.
Here’s an atmospheric video of a male swooping overhead in the Peruvian twilight. What a marvellous bird is the nightjar!
Here’s a male catching insects:
Here’s a male roosting during the day:
And here’s a very patient nesting female from Columbia:
And finally, to prove that it’s not all lyre-tailed nightjars out there in Peru, Holly tw**ted this stunning picture today:
— Holly O´Donnell (@hollyodonnell00) November 2, 2015
JAC: I’ve encountered that species in the tropics; it’s spectacular!