San Nicolas Island (contd) 
Larus Qccidentalis ca . 3^500 
The numbers of this species have increased from the estimated 2,000 
birds on the island on 5 March. The birds continue to defend territories. 
There are a small percentage (less than 10 percent) of the birds that are 
now paired. In three hours of observation, only one bird was seen to de¬ 
monstrate any"breeding/nesting behavior". The animal was tearing vegeta¬ 
tion from the ground, but it did nothing further with the vegetation after 
it had been broken loose. This may have been an effort to clear an area 
for a "scrape" in which to place the nest as the nests of this bird are 
generally in scrapes with only a small amount of nest material. 
On 5 and 6 April the birds were present on the territories. But on 
the morning of 7 April all but a few of the birds had departed the island. 
This behavior is apparently normal for gulls in early stages of the breed¬ 
ing cycle. 
Numenius americanus (Long-billed Curlew) 
While observing the Western Gulls on the west-northwest end of the 
island, one curlew continually circled over my head, calling loudly. The 
bird was seen in the same area on two different days, and, although they 
are not recorded as breeding on the island, I believe this bird was on 
territory. 
Mirounga angustirostris 
Predictably, the age structure of the San Nicolas population has 
changed since the March visit to the island. There are now no adult males 
and few adult females on the island. The yearlings which were in low 
numbers during the last visit have returned to the island. Some of the 
pups have departed the island but a large percentage remains. The tags 
which were placed on these animals in March are holding up well, although 
some of the numbers on the plastic tags are showing signs of wear. There 
is no sign of necrosis (in the tissue) around either the plastic or monel 
tags. The plastic tags are easily read by an observer walking through the 
sleeping animals. The numbers can be read without disturbing or having 
to handle the animals. Table 1. summarizes the Mirounga survey. 
TABLE 1. Census of Mirounga angustirostris , San Nicolas Island, 7 April, 
1968. 
F ema le Ma le Unkn own 
Adult 
Subadult 
Yearling 
Yearling/Subadult* 
Pups 
13 
6 2 ** 
6 
93 
132 
165 
90 
112 8 387 Total 507 
* Yearling/Subadult group closely packed together and ages not distinguish¬ 
able. 
** One of the animals with a small proboscis, age ca_. 7-8 years. 
