The Forster Tern 
FORSTERI, and not hirundo , is really 
the “common,’’ middle-sized tern of Cali¬ 
fornia. Whether upon the interior lakes, 
where it reigns supreme, or upon the bars 
and beaches of southern California, it is 
the only member of the forsteri — hirundo- 
paradiscea group which the casual observer 
is likely to encounter. In migrations this 
species appears freely along the coasts, and 
it undoubtedly mingles more or less with 
migrating hirundo, for specimens of both 
species have been taken at a single dis¬ 
charge.’ And yet we judge that forsteri 
does not occur so often nor so abundantly 
in the great off-shore movement, and that 
it exhibits a greater proprietary attachment 
than do the other species for the brackish 
lagoons and harbor bars. 
As in the case of so many other shore- 
bird species, the migratory movement of 
forsteri is rapid and business-like in spring 
but more leisurely and diffused in the fall. 
Forster’s Tern is preeminently a marsh- 
loving species, and its summer range in¬ 
cludes such of our larger lakes as have 
shallow borders, and the great overflow areas 
tributary to the San Joaquin and Sacramento 
rivers. The birds arrive in late April or early May, but they take only 
a languid interest in local affairs until late May or early June, or until 
such time as the water levels for that season are fairly established. The 
Forster Tern is one of those species which is peculiarly at the mercy of 
the elements. Normally, it constructs a well ordered cone (a shallow 
frustum, to be exact) of green herbage, water-weeds, and half-laced 
sedges, with contents lifted well above the moist earth;but frequent exper¬ 
ience of disastrous flood has driven the birds to adopt various expedients. 
Chief among them is the seizure of other nests more fortunately conceived, 
as for example, those of the Western Grebe (Aschmophorus occidentalis). 
Although the grebe has a cruel beak, she seems unable, or unwilling, to use it 
in self-defense, and will not contest possession with the saucy tern, even 
though her own eggs be half incubated. The nest shown in the illustra¬ 
tion on page 1446 happened to be a fresh one, upon which the tern had 
1 Notably at Hyperion in Los Angeles County. See Condor, Vol. XVI., p. 41. 
Taken in Merced County Photo by the Author 
A SYLPH-LIKE CREATURE 
1444 
