Excerpts from Jim Conrad's
NATURALIST NEWSLETTER

from the October 13, 2008 Newsletter issued from Yokdzonot, Yucatán, MÉXICO
CAVE SWALLOW

I entered the cenote via a steep, wooden staircase, the air becoming ever more humid. A feeling for the pit is provided by a picture of the opposite wall below:

CAVE SWALLOW habitat

The dangling items are the rootlike stems, or stemlike roots of strangler fig trees growing at the rim.

About 15 feet from the platform used by swimmers when they slide into the water a single swallow perched on a tiny ledge beneath a shadowy overhang. Using a flash I got the picture of an immature bird shown below:

CAVE SWALLOW

When I saw the above image I was struck by how similar the species is to the much more widely distributed and common Cliff Swallow. In fact, because of the black belt beneath the throat I thought it might be that species. Cliff Swallows don't breed here but they do migrate southward through here at this time of year, toward their winter homes in Brazil and Argentina.

However, in Howell's A Guide to The Birds of Mexico and Northern Central America I read that juvenile Cave Swallow chests are washed with duskiness, while no such duskiness is mentioned for juvenile Cliff Swallows. Also, folks here tell me that the same large number of swallows is present year round, so at least I know there's no large influx of migrant Cliff Swallows right now. Therefore I'm calling what's in the picture a juvenile Cave Swallow with maybe 95% certainty, and if I'm wrong I know I'll hear about it.

Cave Swallows display an interesting distribution pattern. A population lives permanently in north-central Mexico, during the summer expanding its northern limits into the nearby southwestern US. In far southern Mexico, in Chiapas, a small, isolated population also visits just for the summer. And then here in the upper Yucatán Peninsula we have another isolated but permanent population.


from the October 26, 2014 Newsletter issued from Río Lagartos, on the north-central coast of Yucatán, MÉXICO
CAVE SWALLOWS ON A WIRE

Eight species of swallows can be seen in our area, so when about fifteen birds turned up perched close together on an electrical wire running along the picturesque street next to Río Lagartos's seawall, the Malecón, I wondered who they might be. You can see a couple below:

Cave Swallow, Petrochelidon fulva

An Important field mark to notice is that the birds' tails are only slightly notched, so they're not the Barn Swallows with deeply forked tails the visiting Northerner might expect. Also, despite the silhouetting caused by the bright background, an orangish color can be see on one birds throat, while the other bird displays similar orange color on the bottom near the tail.

These two features narrow down our possibilities to the Cliff and Cave Swallow. Some field guides show Cliff Swallows with squared tails and Cave Swallows with slightly notched ones, but Howell says that the tails of both of those species can range from squared to slightly cleft. The main difference Howell seems to find is that on the upper breast of the Cliff Swallow the orangish throat darkens at its base, strongly contrasting with the whitish underparts, while on Cave Swallows there's no such strong contrast.

Our birds don't seem to have a hint of that dark splotch below the orangish throat, the transition from throat to breast appearing gradual, so that's a vote for their being Cave Swallows. Another vote is that Cave Swallows are permanent residents here and I've often seen them here where they live in sinkholes, locally known as cenotes. However, Cliff Swallows only migrate through the area and I can't recall seeing them.

Still, even Howell admits that, especially in the Yucatan, juveniles of the two species can be confused.