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!