2 A. WiDMANN, Gabberet Isla7td Bird Roosts. I Jan." 



decrease, though still plentiful until a cool spell about the middle 

 of the month, after which only a few hundreds were remaining, 

 and the last were seen on the 24th. In July and August some of 

 the Martins arrive in the vicinity of the roost as early as an hour 

 before sunset, alighting on isolated trees along the shores, or 

 soaring high above the island. Half an hour before sunset some 

 begin to alight on the sandbank, preferably on parts lately 

 exposed and still damp. From now on Martins are pouring in 

 from all sides, sometimes in regular streams, some more or less 

 high, others low over the water, on which innumerable splashes 

 reveal their presence at long distances. 



At sunset a glance over the sandbank reminds one involuntarily 

 of a sheet of sticky fly-paper, well covered with flies, so thickly 

 dotted is the sand with Martins on areas of ten to twenty acres in 

 extent. After the sun has set the Martins leave the sand in 

 detachments and begin to mass and revolve above the willows. 

 During the following ten or fifteen minutes there is a constant 

 flying up from the sand and a coming of new arrivals, which take 

 their places on the sand. 



While the host on the sand is getting slowly smaller, the cloud 

 above the island grows fast and forms a whirling mass of excited 

 birds, uttering low and short, though melodious, calls ; everyone 

 moving in circles of its own, but the whole cloud swinging hither 

 and thither, now low, then high, now contracting, then expanding, 

 sometimes almost disappearing in the distance, then rolling back 

 again in an instant, only to enact another stampede in another 

 direction. 



About twenty minutes after sunset the first Martins descend 

 into the willows. This descent reminds one of that of Swifts into 

 a chimney. The revolving cloud becomes funnel-shaped, almost 

 touching the treetops, and a number of birds drop from the funnel 

 into the willows, while the rest of the birds sweep on, rushing 

 out and scattering in all directions, but in a moment all are flowing 

 back, and the performance is repeated again and again until all 

 are down. 



During the early part of the evening we notice hardly any other 

 kinds of Swallows among the Martins, but after sunset, when they 

 begin to circle, we become suddenly aware of the presence of a 



