BIRDS OF ESSEX COUNTY. 281 



pings. I have dissected a young Tree Swallow shot at Ipswich on September 

 1st, and found 41 of these berries in its alimentary canal. I have never found 

 these berries in the other Swallows. 



Tree Swallows commonly pass the night at this season in willows or elms, 

 from which they arise with a loud whirring of wings when disturbed in the early 

 morning. They often seek the south side of a barn roof to sun themselves in 

 the morning. The numbers in these large flocks may reach two or three thousand 

 or more individuals. 



On the sand beaches they may be seen coursing up and down, picking up 

 insects close to the sand, especially in the vicinity of dead fish. They fre- 

 quently alight on the beach. In 1877, I noted that they collected in large flocks 

 and frequently alighted on the rocks and bushes of Kettle Island, off Magnolia. 

 On barn roofs and in the flocks on the telegraph wires and elsewhere one may 

 often see with the Tree Swallows, the Barn, Cliff, and Bank Swallows, and at 

 Ipswich, near the sea, I should place the relative abundance of these birds in 

 that order, the Tree Swallows far outnumbering all the rest. 



At this season when they are flocking preparatory to the journey south, 

 they may often be seen flying about holes in trees or posts, or bird-houses, as 

 already described, and picking up feathers in their bills as they fly. 



Being able to feed as they fly, the Swallows all migrate by day, and distinct 

 migratory movements can often be watched. At times, great flocks, after rest- 

 ing, rise up in irregular circles, sometimes driving together and whirling about 

 like columns of smoke, all the time rising higher and higher. On reaching a 

 considerable elevation they disappear towards the south. At other times they 

 may be seen flying south in scattered ranks high in the air, only a few coming 

 close to the ground, while again they skim along in their southward flight close 

 to the earth, turning back for a minute occasionally but for the most part press- 

 ing southward. Anon, they all alight in the bayberry bushes to rest and feed, or 

 they cover densely the upper parts of the beach or the smooth sides of sand 

 dunes, making short e.xcursions and returning again to rest before continuing on 

 their way. 



Estimates of the numbers of these flocks are perhaps vain to attempt, and 

 are impossible when the air is filled with the birds, but a few counts made as the 

 birds were passing, may be worth recording. On September ist, 1904, the Tree 

 Swallows at Ipswich Beach appeared to be almost constantly flying south between 

 the hours of 6 and 11 a. m. In five minutes, between 9.10 and 9.15, I counted 

 187 flying south close to the beach between the dunes and the sea, and many 

 were flying over the dunes. Between 9.20 and 9.25, 129 flew by. On Septem- 

 ber 5th, 1904, in the Ipswich dunes the numbers were very great ; 500 flew 

 south overhead between 12.45 and 12.50 p. m., and again, I counted in two 



