374 Roberts, Colony of Yellow-headed Blackbirds. [oc\ k 



stray nests are built among the low rice stubble, this bringing the 

 bottom of the nest almost to the water-level, a precarious position, 

 since a very little rise in the water in the slough would submerge 

 such nests. 



The first day that the reed-clump selected was examined only 

 three nests were found, one about completed and two just begun. 

 During the next two days — May 14 and 15 — twenty-eight (28) 

 nests were tagged. Nest-building was then at its height and for 

 some days thereafter intense activity was displayed. New nests 

 were started almost daily until the end of May and one as late as 

 June 2. These later nests were probably, as will appear further 

 on, the work of unskillful birds that had failed in their earlier 

 attempts. In all, sixty-two (62) nests, counting unfinished attempts 

 as well as completed nests, were discovered, tagged, and subjected 

 to daily scrutiny in this one clump of reeds. Leaving the recital 

 of the detailed notes made during the thirty-two days to form an 

 addendum to this paper, a general summary of the findings may 

 here be presented as being of chief interest to the general reader. 

 For a clear understanding of how some of the observations were 

 obtained it should be stated that many hours were spent at various 

 times throughout the month in quietly watching, glass in hand, the 

 workings of the colony from a convenient distance. 



It was never possible to tell just how many pairs of Yellow-heads 

 composed this colony; but probably thirty pairs is not far from the 

 correct number. 



The females did all the work connected with the nest building, 

 the males taking no part whatever. 



The females incubated the eggs without any assistance from the 

 males, except that occasionally the males brought food to their 

 sitting mates. 



While the nests were being built and the eggs incubated the 

 males remained about the locality part of the time, perching on the 

 reed tops and occasionally showing some interest and concern, 

 especially if a hawk, bittern or other large bird appeared; but they 

 were more often absent roving about the neighboring upland in 

 little parties, foraging for food and amusing themselves. All the 

 birds, females as well as males, seemed to leave the nesting place to 

 feed and could be seen departing or returning in little straggling 

 bands, this being especially noticeable morning and evening. 



