NORTH AMERICAN MARSH BIRDS 199 



with their bills and then assume a quiet pose, side by side, the plum- 

 ;age as smooth as usual. Or perhaps the female alights in a tree where 

 the male is standing; with plumage erected, she courts his attention 

 with a squawk of invitation; he responds in the same manner, comes 

 to her and mounts her, holding her head with his beak, spreading his 

 wings and erecting his plumage. Thus the conjugal pact is sealed. 

 If another male alights near them, the female urges her spouse to 

 •drive him away; and he does so, with much squawking and ruffling 

 of plumage, and with many savage bill strokes and wing blows. 



Similar plumage displays are seen all through the breeding season, 

 in this as in all other herons, as mutual greetings, in the ceremony of 

 nest relief and when feeding the young. They seem to be expressions 

 •of love or sexual emotion. 



Nesting. — My acquaintance with the Barnstable rookery began in 

 1897. It then occupied a heavily wooded area near the southern 

 -edge of the sand hills ; the center of abundance seemed to be in a large 

 deep hollow where the red oak, sassafras, and maple trees grew to a 

 height of 25 or 30 feet. I remember standing in this hollow one day 

 in the winter when the leaves were off, and counting 275 nests in sight 

 from one spot. The herons were still occupying the same nesting 

 ^ite in 1908, but the colony had increased greatly in size ; myimpres- 

 ision was that it had nearly doubled, and it had spread out over a 

 much larger area, nearly half a mile long and an eighth of a mile wide. 

 The nests were placed in pitch pines, red oaks, maples, scrub oaks, 

 .and sassafras, mainly in the oaks, often two or three nests in a tree 

 And sometimes as many as four or five. The so-called sportsmen of 

 the neighborhood found the herons useful as targets on which to prac- 

 tice, and their constant persecution forced the herons to move to a 

 oew nesting site about a mile farther out on the neck. Here we found 

 them in 1910, occupying a mixed tract of pitch pines and oaks on the 

 borders of a cranberry bog in a hollow among the sand dunes. We 

 ■estimated that the colony contained from 1,500 to 2,000 pairs of her- 

 ons. The main portion of the colony was closely concentrated in a 

 .grove of small pitch pines, from 15 to 20 feet high, with a dense 

 undergrowth of scrub oak and an almost impenetrable tangle of cat 

 brier and other vines. 



Three years later, in 1913, we found that the colony had moved 

 again and was located still farther out on the neck, near the extreme 

 -end of the wooded areas, in an extensive grove of pitch pines, with 

 comparatively few oaks. Here it has remained ever since and is still 

 in a flourishing condition. During the summer of 1920, Dr. Alfred O. 

 Gross (1923) camped on the neck for two months and made an inten- 

 sive study of these birds; the published results of his exhaustive 

 study would make an excellent life history of this species. I shall 

 use his data freely, but would refer the reader to his excellent paper 



