One of my favorite things to do in August and September in Florida is watch migrating swallows. Most of the time, 99% of the swallows you see will be Barn swallows. That's not to say they will be boring. There are numerous juvenile birds with shorter tails and variably pale underparts. Adults are also paler than in the spring; many of them will be pale to the point of being almost white underneath. Once in a great while you will encounter what I like to call and Fork-tailed snow-swallow which is a fancy way of describing a leucistic Barn swallow. I've only seen 2-3 of these among the millions of Barn swallows.
Where do you look for swallows in migration?
Where do you look for swallows in migration?
Try edges of water bodies, especially Lake Okeechobee. If you're near the beach, head there. Swallows (and many other birds) use the coast as a navigational aid. Large open spaces like agricultural fields and pastures often attract migrating swallows and make good vistas for observing swallows. Emerging termite swarms, or any other flying insects, are great places to observe swallows as they stop to fuel up. You can often stand in the swarm of insects as the birds fly all around you, close enough to hear the bills snap as they catch their prey.
What do I look for?
Flight patterns can be helpful, but are variable with wind conditions and activity. During high winds or when swallows are actively feeding, flight patterns can vary considerably. Structure and size can help to pick out oddballs.
Wow, this is hard!
Swallows are very fast fliers, so don't get frustrated while watching them. It takes time and patience to get good at swallow ID. Even the best have a hard time identifying avery one.
Some ID Tips for swallows at this time of year in Florida (in order of relative abundance):
Barn swallow - Iridescent blue upper parts. Variably forked tail, nearly always more deeply forked than other species. Dark reddish throat contrasts with rest of underparts. Underparts vary from nearly white in faded individuals or juveniles to reddish or orangish. Long, narrow wings often drawn back to the sides of the body when flapping.
Bank swallow - Underparts very white. Narrow brown breast band sometimes not visible, giving the appearance of completely white underparts. This probably accounts for misidentification of this species as Tree swallow. Tree swallows can occur at this time of year, but most of them don't arrive until October when they gradually become the dominant swallow species. Bank swallows are noticeably smaller than other species with narrower wings and shorter, more slender bodies. Tails are slightly notched, but not nearly so much as all but perhaps the very shortest-tailed Barn swallows. Flight varies from flapping with the wings straight out to drawing the wings back as in Barn swallow.
Cliff swallow - Sometimes more numerous than Bank. Perhaps an earlier migrant. A few known breeding colonies in Florida. Noticeably thicker body and broader wings. Tends to fly with wings straight out. Often flies in roller coaster like fashion. Dark throat pattern similar to Barn swallow. Underparts much paler than most Barn swallows, not showing the reddish tinge of Barn swallows. Upperparts iridescent blue with creamy or buffy, pale rump. Pale forehead often looks like headlamp if the birds are flying straight at you. Tail is short and squared.
Northern rough-winged swallow - Brown on back as in Bank swallow. Underparts variable, but smudgy brown, unlike clear white of Bank and Tree swallows. Flight pattern is similar to Barn swallow. More common around Lake Okeechobee where 100's or even 1000's are known to overwinter.
Purple martin - Most of these pass through before August. Those that remain are usually juveniles. Much larger than other swallows. Big body, broader wings, notched tail, and fairly uniform gray underparts.
Tree swallow - A few usually trickle through in August before the hordes arrive in October. Bright white underneath. Some juveniles have have s slightly dusky breast. Females are duller than males, but adult male and female show iridescent green on the back. Juveniles can be brown on the back, making them look more like Bank swallows. Tree lacks breast band, which can be invisible on some looks at Bank, are usually brighter white underneath and have broader wings and thicker body than Bank swallow.
Cave swallow - Very rare migrant or lingering breeders. Many Cave swallows breed under bridges in eastern Miami-Dade County. These may disperse to other areas in late summer. Cave swallows from Texas may wander around to the east side of the Gulf of Mexico into Florida. Very similar to Cliff swallow. Rump and forehead usually more rusty colored. Throat not as dark as Cliff, orange color extending up the side of the head and behind the eye. Flight pattern more similar to Barn swallow, tending to draw wings back toward body more so than Cliff which usually keeps wings out from body.