316 Swartu, Marsh Wrens of California. Fer 
scattering individuals occurring northward in the San Joaquin 
Valley and along the coast at least as far as Marin County. The 
presence in the series from Oregon, however, of a typical example 
of plesius (a winter bird) from Corvallis, in the northern coast 
region of this state (University of Oregon Mus. No. 1081) shows 
that individuals of this form may occasionally be found in winter 
at any point along the coast. 
The subspecies is generally regarded as a winter visitant, only, 
on the Colorado Desert (see Grinnell, Univ.’ Calif. Publ. Zodl., 
vol. 12, 1914, p. 211), as in the San Diegan region, but there is one 
specimen in the Morcom collection collected at Fort Yuma on 
May 7, a date which suggests the possibility, at least, of its being 
a breeding bird. The extensive series from southern California 
contains few specimens which are helpful in determining average 
dates of arrival and departure, most of them having been taken 
from November to February. The earliest date represented is 
for a specimen from San Pedro, October 3, but it seems probable 
that the species arrives in southern California some weeks earlier. 
The latest date from southern California, aside from the Fort 
Yuma example above mentioned, is from Mecca, about the center 
of the Colorado Desert, April 17. 
The series of plesiws here assembled exhibits a rather wide range 
of variation, both as to color and size, so much so as to suggest the 
possibility of more than one recognizable form being included 
under this name. This suspicion is emphasized by the appearance 
of six fall birds from Nampa, Idaho, which are of an extreme 
grayness of coloration not to be matched by any winter birds from 
California. The status of these several series, however, is a prob- 
lem to be solved by some future worker with an abundance of 
breeding birds from appropriate localities. In series of winter 
specimens of this or comparable species there are sure to be many 
intermediates, sometimes extremely difficult to recognize as such, 
and always hard to adjudge as to their real significance. So it 
must suffice to say here that, compared with the Idaho specimens 
(which may be presumed to be fairly typical of plesius), winter 
birds from California are, with hardly an exception, more richly 
colored, less grayish, and with appreciably darker flanks. This 
generally darker coloration is by no means correlated with small 
