Column headings:
A: No.
B: Wing
C: Longest tail feather
D: Shortest tail feather
E: Exposed culmen
F: Tarsus
=========================+====+=========+=========+=======+=======+======
LOCATION | A | B | C | D | E | F
-------------------------+----+---------+---------+-------+-------+------
_Thalasseus bergii pelecanoides_ | | | |
Palaus, Carolines, | 6 | 343 | 168 | 82 | 60 |
Marshalls | | 334-352 | 153-184 | 80-85 | 58-65 |
| | | | | |
Christmas, Phoenix, | | | | | |
Tuamotus, Society, | 48 | 344 | 170 | 83 | 58 | 27
Fiji, Loyalty, | | 329-362 | 145-198 | 77-92 | 54-64 | 25-29
New Hebrides | | | | | |
| | | | | |
Eastern Australia | 14 | 345 | 165 | 88 | 58 | 27
| | 338-349 | 152-174 | 84-92 | 55-63 | 26-29
| | | | | |
New Guinea, Bismarck, | 18 | 342 | 168 | 81 | 59 | 27
Archipelago, Moluccas| | 332-361 | 144-194 | 75-87 | 53-64 | 26-28
+----+---------+---------+-------+-------+------
Totals | 86 | 344 | 169 | 83 | 58 | 27
| | 329-362 | 144-198 | 75-92 | 53-65 | 25-29
| | | | | |
_Thalasseus bergii cristatus_ | | | | |
Philippines, China, | 18 | 332 | 162 | 81 | 58 | 28
ormosa, Riu Kius | | 324-342 | 149-182 | 78-87 | 55-64 | 26-30
| | | | | |
_Thalasseus bergii gwendolenae_ | | | |
Western Australia | 14 | 354 | 171 | 86 | 58 | 27
| | 339-369 | 162-182 | 81-91 | 53-65 | 25-29
-------------------------+----+---------+---------+-------+-------+------
Measurements, as shown in table 20, indicate a wide range of sizes but,
in most series, the averages are nearly the same. Nevertheless, it is
evident that birds from the coast of China, the Riu Kius, Formosa, and
the Philippines have a distinctly shorter wing than birds from the
Moluccas, Melanesia, eastern Australia, Polynesia, and Micronesia.
Further evidence of this is presented by Kuroda (1925:186) who lists the
measurements of the wing of eight Crested Terns from the Riu Kiu Islands
as 322 to 340 (average 330). The occurrence of populations with shorter
wings has already been pointed out in the work of Oberholser
(1915:520-526), who divided the short-winged birds into two subspecies.
It seems advisable to recognize but one subspecies, _T. b. cristatus_,
for the birds with short wings and another subspecies, _T. b.
pelecanoides_, to include the birds with the longer wings (see figure
11). The average measurements of the length of wings of these two
subspecies, 332, and 344, differ significantly, although there is some
overlap in measurements. A few specimens at hand from the western part
of Malaysia are in poor condition and not measurable.
[Illustration: FIG. 11. Geographic distribution of _Thalasseus bergii_.
(1) _T. b. bergii_; (2) _T. b. thalassinnus_; (3) _T. b. velox_; (4) _T.
b. cristatus_; (5) _T. b. gwendolenae_; (6) _T. b. pelecanoides_.]
Most specimens of _T. b. cristatus_ and _T. b. pelecanoides_ have
lighter-colored upper parts than specimens of _T. b. velox_, but not so
light-colored as specimens of _T. b. gwendolenae_. Size probably is a
better character than color to use in separating these groups.
In Micronesia, the NAMRU2 party observed Crested Terns at Ulithi,
Peleliu and Truk, in August, September, and December, 1945,
respectively. Birds were seen as singles or in small groups flying over
the reefs. The birds were wary and difficult to approach, but they were
conspicuous and easily identified.
=Procelsterna cerulea saxatilis= W. K. Fisher