Fifty-first Progress Report—-Kure Atoll p 4. 
th 
towards the end of the period. The first Brown Booby egg hatched on the 25 
Eight Blue-faced Booby eggs hatched duringt the period. 
The decrease in the number of Great Frigatebird nests is due to a more 
4 
thorough chock of tho north roost# Sovor&l aro&s thst X thought hs.d nosts 
because of displaying males did not have any on closer examination# I do 
not think my distrubance had any effect on the birds# Mainly because I have 
not walked through most of the north roost and secondly because incubating 
frigates are very reluctant to fly# In one area I flushed three birds from 
their nest to get berlese material. The only loss occured when other frrgttes 
destroyed the egg. The other two nests are still active. In the case of the 
Red-footed Booby, distrubance during the construction of theses nest easily 
causes the birds to desert. 
Egg laying in the Red-footed Booby is progressing rapidly. Nests are 
present in the north roost, central roost, and on the east side of the runwaey. 
There are still many nests still under construction. This species nests low 
in the Scaevola thus making it hard to get an accurate idea of the number of 
nests. 
About 20$ of the Red-footed Booby population is composed of subadults 
while at least 50$ of the frigates are in this age class. 
Sooty Terns are now breeding in three sppartte areas- the central roost 
northwest side of the north roost, and on the east side of the antennat field. 
Egg density in all areas is low. In the first few days of the period, birds 
were present only in the central and north roosts. Then on 19 May thousands of 
birds were present under the guywires where last year's colony was. Egg 
laying was rapid and each day moved further south towards the runway until the 
Coast Guard had to drive them away to prevent collisions with aircraft. The 
area in the north roost where thoundsands of 
