BARN SWALLOW 455 



I once had a large, black cat that was a great bird catcher; he would 

 lie hidden in the tall grass and watch for passing swallows; one day 

 I saw him leap into the air and catch a swallow, as it swooped low 

 over the grass tops. Forbush (1929) says: "The appearance of a 

 strange cat, a weasel or a Sharp-shinned Hawk, when the Swallows 

 have young, is the signal for a concerted assault. I have even seen 

 a lone pair of breeding birds drive both cat and weasel from the 

 neighborhood of their helpless young." 



The young in the nest are often attacked by parasites, such as the 

 larvae of Protocalllphora,' the maggots of these flics are very de- 

 structive to young birds of many species, attaching themselves to the 

 eyelids, or entering the throats or nostrils, and probably causing the 

 death of many young. Mr. DuBois tells me of how a barn swallow 

 met its death by a very strange accident; in spite of its dexterity 

 on the wing, it darted into the path of a flying golf ball and was 

 killed by it. 



Fall. — In the northern portion of its breeding range, where only 

 one brood is raised, the fall migration begins early, or soon after the 

 young are strong on the wing, probably early in August. Wendell 

 P. Smith (1937) says of the birds that he studied at Wells River, 

 Vermont : "Flocking evidently began about July 15, as flocks larger 

 than family units were first seen on that date. Migration seemed 

 under way by August 2, and local breeding birds seemed largely gone 

 by August 18." In southern New England barn swallows are common 

 enough in flocks all through August and part of September, but many 

 of these may be birds that have come from farther north. The mi- 

 gration seems to be largely coastwise; we always see plenty of them 

 on outer Cape Cod, during late summer and early fall; they scatter 

 out over the marshes, coursing about independently to feed on the 

 millions of mosquitoes and flies; on windy days, I have often seen 

 them resting in compact flocks on the "back of the beach" (ocean side), 

 squatting low in the sand and all facing the wind. 



They seem to prefer to migrate by day and, strangely enough, often 

 against a strong south wind. Some of them fly high in loose formation, 

 but oftener they move along within 100 feet of the ground or lower. 

 They may often be seen moving along the coast line, or the bank of 

 a river, only a few feet above the ground or water, in a steady open 

 stream, all following the same general direction but without any 

 definite flock formation. They have been seen at sea, and must 

 regularly migrate across the Gulf of Mexico to reach their winter 

 range in South America. 



Dr. Winsor M. Tyler contributes the following observation : "In 

 the inland country of New England we see the last of the barn swal- 

 lows during the first week of September, often in small parties, 



