YELLOW-HEADED BLACKBIRD 115 



heads, and redwings, arose in a cloud all over the marsh and flew 

 about for a few minutes, cackling and squealing, until the hawk 

 departed; this happened several times, whenever the hawk appeared. 

 Others have noticed similar behavior. Linsdale (1938) saw a black- 

 bird fly after a marsh hawk, "but the pursuit was spiritless." He 

 noted that, when a prairie falcon circled overhead, they gave the 

 alarm and ' 'hurried to the cover offered by a bush." They also 

 gave alarm and flew at a Swainson's hawk that flew over; they were 

 disturbed by a nighthawk, but did not attack it; two crows were 

 driven away. Wetmore (1920) saw them driven to shelter by a 

 marsh hawk. 



On the ground, the yellowheads walk sedately, seldom hopping, 

 or run rapidly in pursuit of a moving insect. Of their flight, Linsdale 

 says: 



"The flight of the yellow-headed blackbirds contrasted markedly 

 with that of the red-winged blackbirds. It was slow and deliberate 

 and seemed to reflect the whole manner of the species. The dull 

 whistle made by the wings could be heard distinctly for 50 yards 

 or farther as the birds flapped heavily from one perch to another." 



Wetmore (1920) comments on the perching ability of the birds as 

 follows : 



The feet of the Yellow-head are relatively very large with long, strong toes and 

 the birds use them to advantage in walking about on floating aquatic vegetation 

 or soft mud. In the rushes they prove themselves expert gymnasts. Often they 

 alighted near the tips of the tall round-stemmed tules and as they swayed under 

 their weight the birds supported themselves by their wings while they slid their 

 feet quickly down to a new hold, trying several grips until finally they were low 

 enough so that the rush supported them. This was done with great quickness 

 as the birds shifted from grip to grip rapidly. At times instead of sliding down 

 they reached out and grasped a second stem with one foot, dividing their weight 

 between the two and standing suspended with the feet five inches or so apart. 



On the subject of combativeness, Ammann (MS.) writes: "Judging 

 from the behavior of nesting Yellow-heads toward humans, the male 

 is more pugnacious and aggressive than the female. On several 

 different occasions while I was banding four- or five-day-old young 

 the male darted at my head and narrowly missed me. Once after I 

 had picked up a fledgling the male flew at me quite forcefully, striking 

 the side of my head with his bill. On another occasion I was in a 

 blind and saw an adult male molesting a fledging. Much to my 

 surprise another adult male immediately attacked the intruder and 

 a short combat in mid-air ensued. Both feet and bills were brought 

 into action. In a few seconds the assumed father of the fledgling 

 got the better of the intruder and while holding him down, half sub- 

 merged on some floating vegetation, pecked viciously at the back of 



