by Frank Keim
Many years ago while a friend and I were watching Bank swallows fly in and out of their cavities near a Yukon River village, he told me to watch as he tried to catch one of the little birds when it flew out of its hole. I thought he was joking, but very quickly he proved otherwise as he cupped his hand around the entrance and waited for a swallow to fly out.
It took only the blink of an eye for him to do as he said, and quick as lightning he held one gently in his hands. Although I privately thought it was a danger to the bird’s safety and an invasion of its privacy, I complimented my friend for his prowess. I was half kidding, but had to admit he was pretty good at it.
Bank swallows may not be very fast leaving their holes, but they certainly are speedy as they zip through the air with their fluttery wingbeats and acrobatic twists and turns. I still see them every summer in their chattering colonies catching insects over the water near where their burrows have been excavated into the steep banks and bluffs of rivers I float in Interior Alaska.
These colonies can sometimes number up to 2000 individual cavity nests, with birds flying everywhere above the water while totally avoiding the forests lining the river on both sides. Look for handsome small brown swallows with a brown band across their chests and quick, fluttery wingbeats, then listen for their strident, double-call notes as they chase flying insects like bees, wasps, ants, butterflies and moths.
These swallows get back to the YK Delta from their South American winter homes in May. Individuals from both sexes immediately choose a colony, then the male selects a nest site in the colony area with firm soft soil on the side of a vertical cliff or bank near or above water where there is ample airspace for flying and catching insects. He then uses his small conical bill, feet and wings to dig a horizontal tunnel about two feet long into the side of the bank.
At the end of the tunnel he enlarges the space upward and to both sides to form the nest chamber. After he finishes the nest burrow, he then begins his ritual courtship and territorial circular flights around the nest site while singing his sweetest twittering song.
Often he darts about carrying and dropping a white feather to attract the interest of a circling female. If she is interested, she then hovers in front of the hole entrance to check out the quality of his work. Based on her appraisal, she chooses her mate and his nest site.
She then sets to work building her nest, a flat mat of woven grasses, leaves and small willow roots found inside the burrow while excavating the nest. The nest is almost always located above and below the reach of ground predators.
This is where the various Yup’ik names for Bank swallows come in. Three I found are: Ekvigtaar(aq), meaning “one that nests in a cliff hole;” Kauturyar(aq), which loosely translates as “one that makes its nest inside a dark hole;” and Aguumar(aq), meaning “one that weaves its nest like a basket from small willow roots.”
If the male is successful attracting a mate he will defend the burrow and its immediate surroundings from other males, but if he is unsuccessful he will abandon the burrow. Bank swallow pairs remain together for the breeding season, but both members of the pair often breed with other individuals in the colony as well.
Three to five white eggs are laid in the willow root nest, and incubated by the female for about two weeks. After hatching, the naked pink hatchlings grow feathers quickly, and by the end of three weeks have fledged and left home to become expert aerial predators just like their parents. Also like their parents, they are extremely social birds, flying either in the company of other Bank swallows or among other species of swallows. This is for good reason, because often quite near and not far above them there might be a Peregrine falcon aerie with some very hungry chicks.
In the event of an extreme period of cold weather they will also huddle with other swallows to stay warm. Their sociability applies during migration, too, and they will travel with many different species of swallows to warmer climes.
In addition to its common name, Bank swallow, which is descriptive of where it nests, it has three other common names: Sand swallow, Sand martin, and Bank martin. Its scientific name, Riparia riparia, has a similar meaning, “frequenting riverbanks.”
Bank swallows are one of the most widely distributed birds in the world, found everywhere except on the continents of Australia and Antarctica. Sadly, their North American numbers have crashed by almost 90 percent since 1970.
Human habitat loss is one factor responsible for the crash, but more important is the extreme loss of insects all over the country due to the use of neonicotinoids and other insecticides. Only after the United States follows the lead of the European Union and Canada in banning their use will swallow numbers hopefully begin to rebound.
