450 THE ZOOLOGIST. 
generally lay about three eggs, but if anything happens to the 
first ones they lay again. They are rather restless sitters and 
very anxious about their eggs, having found out that the Rooks 
are constantly on the look out to suck them, and are often 
successful if both leave the nest, for a few moments even, 
to feed; so now they seldom both leave the nest together, one 
always remaining either on, or close by, the nest after the first 
egg is laid. They always choose the same place at the foot of 
the stump of an old walnut tree which was blown down some 
years ago, the stump having been left standing for them. 
Two Lesser Black-backed Gulls were sent to me from Alderney 
in July, 1879, almost in the down and quite unable to fly. They 
are, I suppose, both females, as they have not paired with each 
other; but in May, 1880, by which time they had both assumed 
fully adult plumage, one of them paired with an adult male Herring 
Gull. She laid three eggs, but only one was hatched. The young 
bird was just able to fly by the 30th July, when we caught it and 
cut its quill-feathers, but unfortunately did not pinion it. At this 
time it was impossible to distinguish it from a young Herring 
Gull of the same age. Owing to a long absence from home, 
I found this bird and the young Herring Gull of the same age 
able to fly well, and it was quite impossible to catch either of them. 
Both remained here, however, till May of the present year; but 
at that time it was almost impossible to tell which was which. 
The only difference I could see was in the colour of the legs, 
those of the cross-bred bird showing more inclination to yellow 
than those of the young Herring Gull, which were then nearly 
the pale flesh-colour of the adult. While I was away both took 
their departure; but one of them, the young Herring Gull, con- 
stantly returns, sometimes remaining several days at a time and 
sometimes departing immediately after feeding time, and not 
making his appearance again till feeding time the next day; but 
Iam afraid the cross-bred bird has entirely disappeared. This 
practice of dropping in at feeding time and remaining a long or 
short time, as may happen, has been adopted by several other 
Herring Gulls this year. Some of them may have been bred 
here and gone away, but one of them is certainly an entire 
stranger, as he is a young bird of the year, and my tame ones 
this year were unfortunate, and did not rear the only one which 
was hatched. Some of the others are, I think, also quite strangers, 
ee 
