316 
PACIFIC SCIENCE, Vol XXII, July 1968 
TABLE 1 ( continued ) 
USNM NO. 
ISLAND 
DATE 
.SEX 
WEIGHT 
IN GRAMS 
Larus schistisagus 
(Slaty-backed 
Gull) 
494373 
Kure Atoll 
9 Mar 1965 
d 
973 
PJssa tri dactyl a 
( Black-legged 
Kittiwake) 
494296 
496205 
496206 
Kure Atoll 
Pearl and Hermes Reef 
Pearl and Hermes Reef 
30 Dec 1964 
15 Mar 1965 
19 Mar 1965 
2 
317.5 
dried carcass 
dried carcass 
gull numbers and the collection of 5 individuals 
in early March, when no more than 3 were seen 
on any one day, would indicate a frequently 
changing population. Therefore more than 22 
gulls may have visited the island during the 
winter. All sight identifications given in Table 
2 are questionable since immature gulls are dif- 
ficult to identify in the field. During two trips 
to the Leeward Hawaiian Islands, 6 gulls of 
three species were collected — 5 birds in March 
and 1 in August. 
Observers present on Johnston Atoll between 
July 1963 and March 1966 saw only 3 gulls, 
one of which was collected. In addition, 2 
specimens were collected at sea, 11 miles and 
300 miles south of Johnston Atoll. 
No comparable data are available from the 
main Hawaiian islands, but since 1961 (during 
the winter months, December to March) obser- 
vations of six species have been reported in 
The Elepaio (Walker, 1961; Bryan, 1962, 1964; 
Ord, 1962, 1963*, 1963b, 1963c, 1964). 
Gulls probably occur irregularly during the 
winter on all of the Hawaiian islands but more 
frequently on the leeward than on the main 
islands. An unexplained fluctuation in numbers 
and species occurs from year to year. During the 
winters of 1962-1963 and 1964-1965, con- 
siderable numbers of gulls were present in the 
Leeward Hawaiian Islands; in 1963-1964, 
none. Larus argentatus and L. glaucescens , the 
most abundant species, were not equally com- 
mon during the two good winters. In 1962— 
1963 L. argentatus outnumbered L. glaucescens 
eight to one, but in 1964-1965 the proportion 
w T as four to eight. Very few of the observations 
have been of adult birds, and there have been 
no summer observations of living birds. 
RECORDS FROM THE LINE 
AND PHOENIX ISLANDS 
Only three published records existed for the 
Line and Phoenix islands. King (1955) re- 
ported an immature Larus delawarensis on 
Christmas Island from 15-17 November 1953, 
Bourne (1965) reported the sighting of "a 
few” L. pipixcan at Fanning Island in Decem- 
ber 1963, and Fry (1966) reported a L. 
occidentalis on Fanning Island in July 1965. 
Thrice-yearly trips were initiated to the 
Phoenix Islands in 1963 and to the Line Islands 
in 1964. Gulls were seen once in the Phoenix 
group and on four trips to the Line Islands. All 
six specimens collected in 1964-1965 (four on 
Christmas Island, one on Palmyra, one on 
Baker) were L. atrkilla and all six sight records 
for this period (two from Palmyra, four from 
Fanning) were referred to this species (Clapp 
and Sibley, 1967). In May 1966 two L. pipix- 
can were collected on Palmyra Island, Line 
Islands. 
DISCUSSION 
Many authors have noted that gulls are 
generally absent from tropical oceanic islands. 
Their distribution is normally associated with 
continental areas or islands adjacent to large 
land masses, e.g., the Australasian region and 
the West Indies. Those gulls which habitually 
spend long periods at sea are restricted to the 
cold waters of the temperate and polar regions. 
