'oct. 1906. 
HERRING GULL AND CASPIAN TERN. 
127 
neighboring young one, which she viciously mauls about the neck. 
This exhibition usually takes place just before she feeds her young 
and likewise between courses, as it were. Why she does this I 
am at a loss to suggest, unless it be mere ill-will. The old bird 
does not always confine this ill treatment to one strange young 
bird, but takes in a circle of those whose parents are absent. The 
young thus rudely treated sometimes bite back, but usually do 
not offer resistance, uttering instead a plaintive little squeak. A 
small mortality is the result of this practice." 
Here again we seem to have a similar habit in a different group 
of birds, and perhaps Fisher's suggestion that it is the result of 
"mere ill-will" is as good as we can offer. At the time of observa- 
tion I suggested in my notes that perhaps the cause was impatience 
at having the young to care for. I have recently asked in 
"Science" for the observations or explanations of others. It 
would be interesting to determine whether both sexes took part 
in this slaughter. 
Several writers speak of the sexes of these gulls as if they 
were readily distinguishable. There is, I believe, no distinction 
at all in plumage, and the smaller size of the female, if it exists 
at all, is so slight that neither Mr. Shrosbree, a taxidermist of 
many years' experience, nor myself were able to predicate the 
sexes of any of the twenty or more adults that w r e skinned until 
we made the necessary dissection. Only in cases were I saw the 
act of copulation could I be certain of the sex of one of the live 
birds. 
When this year I first set up my tent among the gulls there 
were three people in the boat that went to the island. A position 
near the center of the colony was selected, the tent quickly erected 
and my camera and other paraphernalia placed within. While 
my companions were close by I stepped inside and closed the flap ; 
then they went to the beach, pushed off the boat and rowed away. 
Within ten minutes swarms of gulls were hovering low over the 
island and tent and screaming loudly. Within five or ten minutes 
gulls had gathered on the ground within one or two yards of the 
tent. In one hour and ten minutes after the boat left a gull alit 
upon the tent and spent some minutes there screaming, and from 
then until I left the island there was an almost constant succession 
of gulls upon the roof of the tent, and sometimes two at once. The 
