Bank Swallow

Bank Swallow - Our Smallest Swallow 

Bank Swallow

The Bank Swallow (Riparia riparia) is our smallest swallow.  It is 12 cm (4.8 inches) long compared to 14 cm (5.5 inches) of the Cliff Swallow.  The Barn Swallow is much bigger of course because of the long tail (17 cm/6.8 inches).  The Bank Swallow spends its summers in most of North America from Alaska to Newfoundland and Labrador south to the central US.  It winters in southern US, Mexico, the Caribbean and South America.  Because it migrates such long distances it is our first swallow to leave in late summer.  The Bank Swallow is one of the few passerines with a nearly worldwide distribution, amazing for such a small species.  It is also found in Europe, parts of the Middle East, Central Asia, Russia, northern Mongolia, and parts of northern China.  In Europe this species is known as the Sand Martin.

The description of this species is simple, upperparts brown, underparts white with an obvious brown breast band.  Note the white throat above the band.  It has a slightly forked tail (notched) but nothing like the deeply forked tail of the Barn Swallow.  It flies with its pointed wings swept backward. Its wing feathers appear slightly darker than its body.  The only species one might mistake for a Bank Swallow are a young Tree Swallow which can have a hint of breast band (although it is incomplete) or a  Rough-winged Swallow.  The Rough-winged Swallow is uncommon here in New Brunswick and it has a 'dirty' brownish throat and no breast band.

Bank Swallow

'Riparia', the genus and species names of this species, means 'river bank'.  They are well named because they nest in burrows made in river banks.  The St. John River has many nesting areas for Bank Swallows.  Near Fredericton this year there is a colony off the head of Aukpak Island.  Because of river erosion the colony makes its burrows fresh every year.  Bank Swallows are very social birds and the colony times the egg laying so that all nests hatch at the same time.  That way more adults are available to find food for the nestlings.  I imagine they know when the insects will be in swarms so the heavy duty feeding occurs at that time.  Bank Swallows also nest along banks of lakes, coastlines, and other wetlands. Apparently in some places they have learned to use man-made structures.

After the site for the colony is chosen the male begins to dig a tunnel.  The female then hovers in front of the tunnel (and male) she chooses and the pair then complete the excavation using their bills, feet and wings.  The Bank Swallow lays 3 to 7 white eggs in a nest lined with feathers and grass in a chamber at the end of a deep tunnel.  Incubation is for 14 to 16 days and is carried out by both adults.  This species feeds on flying insects which it catches on the wing.  Bank Swallows do not sing but frequently make a buzzy 'trrrt' or 'pret' sound.

The Bank Swallow is a threatened species.  Waterway erosion and human 'development' such as road building and quarry establishments are the prime causes.  There has been an 89% decline in the population of Bank Swallows since 1970!  It is time we examined the insect populations and their declines as well as our own destructive behaviours in order to save this species (and many others).