ML250342551

Age

Not specified

Sex

Not specified

Media notes

Field notes and illustration by Jed Burtt

Observation details

***Mega. First record for the Galápagos Islands. Two individuals were observed by Jed Burtt and Sean Williams at length for 15 minutes. Original field sketch and notes by Jed Burtt attached. As well, below is the original report prepared in 2011 by Williams and Burtt for publication in the journal, Galápagos Research. INTRODUCTION On 21 May 2011 at 16:00, Williams and Burtt watched two large swallows flying low over the vegetation near Punta Suárez, Española, for about 15 minutes. We stood about 100 meters from the birds. The conditions were sunny, with excellent visibility. We observed the birds from several different angles and with front and back lighting. The vegetation in the littoral zone, where the swallows spent most of their time, is saltbush (Cryptocarpus pyriformis), which is short. The birds were flying above the vegetation, at an altitude of 3-6 meters, but sometimes dipped through the vegetation. The birds flapped frequently with deep wing beats. When gliding, the birds held their wings below the horizontal. They had wide wings and moderately forked tails. The fork was less pronounced than that of a Barn Swallow (Hirundo rustica), but more than that of a Tree Swallow (Tachycineta bicolor). Several Galápagos Doves (Zenaida galapagoensis) flew by the swallows, which were approximately the same length or slightly smaller than the doves. In full, frontal light, we saw that both birds had brilliant white bellies and near-white or white throats that contrasted with a broad, dull-brown band across the upper breast. At times, the white undertail coverts seemed to wrap around the tail and were visible on the sides of the brown rump. All the dorsal feathers were dull brown. DISCUSSION Martins (Progne spp.) are an American group of swallows characterized by large size. The swallows we observed were near the length of a Galápagos Dove. The Galápagos Dove measures 20 cm in length and the size range of martins is 16-20 cm (del Hoyo et al. 2004). Martins are the only American swallows in this size range. Moderately forked tails and proportionately broad wings also characterize martins. The large size, broad wings, and moderately forked tails of the birds we saw identify them as martins (Progne spp.). Of the nine martin species, six have white on the belly in some plumage: Purple (P. subis), Gray-breasted (P. chalybea), Brown-chested, Caribbean (P. dominicensis), Cuban (P. cryptoleuca), and Sinaloa (P. sinaloae) (del Hoyo et al. 2004). Of the nine species, eight always have a deep purple or blue gloss on the dorsum, with the gloss covering the entire bird in some species. The exception is the Brown-chested Martin, which is dull grey-brown above (Restall 2006). The Brown-chested Martin also has a distinctive broad grey-brown breast-band, which perfectly matches the chest pattern of the two birds we saw and sketched. Furthermore, the unmarked white belly strongly supports identification of these two individuals as P. t. tapera, which lacks the dusky plumage that extends from the breast band along the central axis of the belly in P. t. fusca (del Hoyo et al. 2004). Ridgely and Greenfield (2001) note that the Brown-chested Martin “often glides on bowed wings” and Restall (2006) states that birds fly “almost invariably near ground.” We saw both traits as described above.

Technical information

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3.44 MB