SECOND WEEK. March 10 through March 16. 
Period 1. March 10 through March 12. Before the gulls 
have come down on the hearth for the first time. 
Aggressive "behavior over hearth area. Aerial. Like that 
described in last weeks notes. Noticed that the gulls attacked 
herons, and sometimes crows. Sometimes, however, crows were 
unmolested as they wheeled in the midst of the flock. Aggressive 
behavior seems to be less common in the main body of gulls than in 
the small outlying groups. Aggressive behavior is also less 
conspicuous when the gulls are flying low in a tightly-pavked 
bunch. Chasing and Swooping are less conspicuous now than when 
we observed them last week, (of course, we were out earlier in the 
day then, as there was no fog last week). We have several times 
observed mutual Swooping, and also Swooping at nothing at all 
(R. Mar 11, 2). 
Aggressive behavior in flooded field. Gulls not territorial 
(M. Mar 11, 1). One very clear instance of courtship on water 
(M. Mar 10, 3). Descriptions of Chase and Swoop; drawings of 
Swoop (M. Mar 10, 5). Around noontime the gulls seem to spend 
their time circling alternately over the flooded field and over 
the hearth. 
We also found some gulls in a distant field, which may have 
served as a field roost. Plenty of aggressive behavior. 
Very conspicuous Erect postures. Courtship? Probably Choking. 
Food-begging. Noticed that Panics very definitely started at one 
end of the flock. 
In general, the behavior of the gulls during this period 
was the same as their behavior last week. Reproductive behavior 
has already begun. Courtship and aggression. Many of the birds 
are probably already paired. It is still doubtful exactly how 
territorial they are at this stage; at least semi-territorial in 
some cases. The gulls only seem to take an interest in the hearth 
for an hour or so in the morning. 
