each season, and in 1980 about 150 
pairs nested in the fenced sanctuary, 
making it the largest in the state. An 
estimated 240 fledglings joined the mi- 
gratory flock at the end of the season. 
The successful reestablishment of the 
Venice colony is an encouraging sign 
that there eventually may be California 
least terns nesting all along the coast on 
beaches from which they were extir- 
pated. 
Proper management of an endan- 
gered species must be based on a thor- 
ough knowledge of its life history. At the 
same time, the study of an endangered 
species must proceed with extreme cau- 
tion in order not to jeopardize the sub- 
ject one is trying to protect. Breeding 
California least terns do not tolerate 
more than a minimum amount of han- 
dling, and our research has been tailored 
to their needs. In 1976, we embarked on 
a long-term study based on color band- 
ing of chicks. The banding is done under 
the auspices of recovery team member 
Charles T. Collins, and my colleague on 
this project is Jon Atwood, a doctoral 
candidate in biology at UCLA. We have 
found that a group of three to five 
experienced people can move through a 
large colony in the early morning and 
collect growth data and color band 
about fifty chicks an hour, after which 
the colony is left to return to its daily 
routine. There have been no untoward 
effects from this procedure. 
We have banded more than 2,000 
chicks since 1976, and since 1978 have 
color coded youngsters so that many 
returning adults can be identified in the 
field as to age and natal colony. We now 
spend many hours during the nesting 
season in a blind looking for and trap- 
ping banded birds. The information be- 
ing sought through banding includes age 
of first breeding, tenacity of the pair 
bond, duration of breeding life, inter- 
colony movements, postseason wander- 
ing, and where the birds go for the 
winter. Data on returning birds are ac- 
cumulating at an accelerated pace each 
year. We have learned that the terns 
begin breeding at the age of two; these 
young birds arrive on the nesting 
Two- to three-day-old chicks are fed 
by their parents. Because the chicks 
have successfully hatched, the adult 
pair will return to the same nesting 
area next year, whether or not these 
young survive to fledge. 
grounds about six weeks after the older, 
experienced breeders, and lay their eggs 
after the first wave of chicks has already 
hatched. None of the larger terns of the 
genus Sterna breeds regularly at such 
an early age, and this finding was quite 
unexpected. When the adults return for 
the first time to breed, they do not 
necessarily come back to their natal 
colony. Once they have bred success- 
fully at a site, however, they show a 
marked tendency to return the following 
year. 
Information on pair bonds is, at this 
stage, ambiguous. Pairs apparently re- 
main together throughout a season, as 
evidenced by banded pairs renesting af- 
ter the loss of eggs or chicks. But the 
tenacity of the pair bond from season to 
season varies. Some birds return annu- 
ally to the same spot in a breeding 
colony with the same mate; others have 
returned to the same or a different col- 
ony with another mate. One pair of 
banded birds “divorced” after a year, 
and the following season each nested 
with a new mate within fifteen feet of 
its previous territory. 
The question of where California 
least terns spend the winter is one of the 
most challenging aspects of our re- 
search. 
When Jon Atwood and I organized a 
group to look for wintering areas in 
December 1978, our only sure knowl- 
edge was that the terns went south of the 
California border, as there were no win- 
tering records in the United States. At 
that time there had been no banding 
recoveries outside the United States and 
we had no clues as to where to begin our 
search. (There has since been one recov- 
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70 
