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Bank Swallow
Riparia riparia (Linnaeus)
Status Common in summer. Breeds. It normally appears in the first half of May (average 8 May, earliest 20 April), but migrant flocks are still evident in early June. It is abundant locally in the immediate vicinity of its breeding colonies during nesting season, after which it scatters widely and is seen less commonly up to the time of
gatherings of migrants in the second half of August. Stragglers are regular throughout September, and very late birds have occurred during four years in November, the latest one on Sable Island on 21 November 1968.
Description Length: 13-14 cm. Adults: Upperparts grayish brown without iridescence; grayish brown band across breast; throat and belly white.
Breeding Nest: At the end of a tunnel in a sand or gravel bank or a steep-sided sawdust pile and always in colonies. The burrows are always near the top of a bank and extend 60-95 cm into it. The cavity at the end is lined with grass and feathers. Eggs: 4-6, usually 5; white. Laying begins about 1 June and nesting operations continue through the first week of August. When the last of the young have flown, the colony locations are forsaken. On 11 June 1917, three nests were examined at a colony of about 200 pairs at Evangeline Beach, Kings County; all contained five fresh eggs.
Range Breeds from northern Alaska to southern Labrador and Newfoundland and, in the east, as far south as some of the southern states. Winters in South America. Found also in the Old World.
Remarks This swallow is distinguished from the others that occur here by its smaller size, brown back and grayish brown band that crosses an otherwise white breast.
Nest burrows are close together and, when the colony is large and space perhaps limited, often arranged in tiers of two or more. Watching a large colony when parents are feeding their young, one is impressed by their ability to tell which nest is their own and by the general lack of confusion and animosity that prevails in the midst of much activity.
I have stated that the nest excavations are "always" near the top of a bank. Perhaps "usually" would have been a better word, but I have yet to note an exception. Positioned as they are at about grass-roots level, they are vulnerable to predators, including inquisitive children who with little effort can dig down or reach from the top of the embankment. If the holes were 2 m or more lower on the perpendicular wall, the nest cavities would be difficult to reach. But the swallows continue to do as they have done for uncounted generations and seem quite capable of maintaining their numbers under the traditional arrangement. Lloyd B. Macpherson suggests that Bank Swallows may choose the top of an embankment because the earth there is more readily excavated than at lower elevations where the compressed subsoil makes digging more difficult.
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