Cerulean Warbler
Common Name: Cerulean
Warbler
Class: Aves
Order:
Passeriformes
Family: Parulidae
Genus: Dendroica
Species:
Dendroica cerulean
|
photo M. Noonan |
Taxonomy/Description
The
Cerulean Warbler is a passerine in the family parulidae.
This family contains all of the species of wood warblers
in the new world. It is in the genus Dendroica –
consisting of northern warblers. The Cerulean Warbler is
a small member of the parulid family at 11.5 cm and
8-10g. Its name Dendroica cerulean depicts this
warbler’s rich blue color. The Cerulean Warbler has long
pointed wings with a short tail. The adult male is a
bold cerulean blue, white below, with a very narrow
blue-black band under the throat and streaked back. The
female is a bluish-green, whitish-yellow underparts, and
a white to yellow eye stripe. Both genders share two
white wing bars and white tail spots.
Habitat/Diet
The Cerulean Warbler has a rather broad, but not
uniform, distribution throughout northeast U.S. It
breads as far west as central Arkansas, Missouri, and
Iowa, north into southern Ontario, throughout New York –
except for in the Adirondack area, and as to the south
in West Virginia and North Carolina. Throughout this
area, this warbler is found in very patchy areas. In
this range, the Cerulean Warbler may be found in
predominately forested areas – mainly in mature forests
of large and tall trees of broad-leaved, deciduous trees
with open understory. It has been found that this
warbler prefers areas where there are distinct
horizontal zones of forest layers, as well as periodic
gaps, or openings, in the canopy. The Cerulean Warbler
is mostly insectivorous and forages in the foliage,
however, it also eats some plant material, especially
small fatty masses that are attached to fruits of some
tropical tree.
Behavior/Reproduction
The Cerulean Warbler
typically hops between branches in the canopy laterally or slightly upward,
rather than walking or climbing. Also, short flights from tree to tree are
common. When a warbler does this behavior, often it will flutter or slightly
flap, spreading its tail to reveal the white patches in the tail and on the
inner vanes of the primaries and secondaries.
Breeding cerulean warblers can be aggressive. Both males and females can be
seen in same sex fights where an attack is made mid-air at canopy levels. As
the birds fall, they fight with one another’s beaks and feet with their
wings and feet spread. Females have also been spotted fighting with females
of other species over nesting material, typically spider webs. In these
cases, it is usual for the cerulean to be displaced.
In this species, males usually arrive at least one week to the breeding
grounds, and pair formation occurs very quickly after females arrive. The
nest is built only by the female, and is usually found mid-story or
overstory canopy of a deciduous tree. It is characteristic for 3-4 eggs to
be laid. This will be the only brood of the season and the female will
incubate it by herself. The female displays a nest defense sometimes
referred to as “bungee-dropping.” This is when the female leaves the nests
by dropping vertically from the side of the nest with the wings closed for a
few meters, resembling a falling leaf with her greenish hue; only after she
is a distance from her nest will she open her wings. This is done to
supposedly distract predators away from the location of the nest.
Where to see them in WNY
The Cerulean Warbler has
been increasing in number in many New York areas. It has been spotted in Oak
Orchard State Wildlife Reserve. Remember – this bird stays high in the canopy –
so look up!