By Rick LoBello, Board Member
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As the audience awaits the rising curtain on the big bat flight show, vociferous Cave Swallows fly overhead in search of a final evening meal. These dive-bombing acrobats must know that they will be forced out of the way by a barrage of Mexican free-tailed bats taking over their air space above the cave.
When I lived and worked at Carlsbad Caverns National Park, every night during the summer when I opened my back door I was aware of this fascinating moment in the daily cycle of life. Rarely could I hear the bats or the swallows as they flew about, but I could always smell the bats as their wings covered with the musty scent of guano and a hint of ammonia filled the air.
Nesting along the walls of the Cavern’s natural entrance, these beautiful birds are often at first glance mistaken for bats. But in stark contrast to the squeaking sounds of the swallows, the near silent exiting of bats is a completely different picture. As the bats fly out after sleeping in the cave all day, the bat flight sometimes creates a large black cloud in the summertime sky, the same cloud that first attracted early Carlsbad explorer Jim White to the cave over a hundred years ago.
From late spring to early fall most people who go to see the evening bat flight at Carlsbad Caverns also get to see hundreds of Cave Swallows. During the Covid-19 pandemic the bat flight amphitheater has been closed, but park visitors can still witness both the swallows and bats at sunset from the parking lot nearby.
At one time Cave Swallows were mainly a bird from Mexico, but over the years they have expanded their range in Texas often forming colonies under bridges. My good friend Steve West has studied the Cave Swallows at Carlsbad Caverns for over thirty years and to this day says there is still much to learn about them. With the help of over 5,000 volunteers from 41 states and 20 countries holding net poles, Steve was able to band over 8,000 birds. The banding project is one of the longest on-going banding studies in the United States.
El Paso Naturalist Dr. Ad Konings has reported Cave Swallows in El Paso at Rio Bosque Wetlands Park in the Lower Valley and in the Upper Valley under a bridge on Sunset Drive. They should be here though the fall so watch for them before they migrate south.
Carlsbad Cavern’s National Park states on their website that in 2005, Steve West recaptured a Cave Swallow that had been banded in 1993 as a hatch-year individual, making it 12 years old! While most of the banding has been done to study the life history of the species, the original reason was to discover the winter range of the bird. One bird banded at Carlsbad Cavern was found dead in Jalisco, on the Pacific coast of Mexico, and provided the first clue of their winter range south of the United States.
The Trans-Pecos Audubon Society reports that are records for eight different swallow species in El Paso County including the Tree Swallow, Purple Martin, Violet Green Swallow, Northern Rough-winged Swallow, Bank Swallow, Cliff Swallow and Barn Swallow. Cave Swallows are dark above and pale below. The most notable colors to look for to identify one include the chestnut rump, forehead, and cheeks, and the pale chestnut throat. Cave Swallows are aerial insectivores that eat insects on the wing. They nest colonially and forage in groups, often with other swallows.
Photo Credits – Swallow nest, John Mangold, Wikimedia Creative Common
Bat flight – National Park Service
All others including the cover on August 11, 2020 – Ad Konings