Wild About Birds - Wood-warblers!

Wood-warblers are members of the Family Parulidae. They are small birds that use their needlelike bill to capture the insects that make up the majority of their diet. Males and females have a similar appearance in some of the species, while in others, the male and female have different feather coloration (dimorphism). In spring and summer the dimorphic males and the males and females of the other wood-warbler species are brilliantly colored, but in fall, most warbler species have drab coloration, and identification may be difficult. Wood-warblers are migratory birds. They winter from the southern United States to South America. Nineteen wood-warbler species are known to breed in Illinois. They are the species featured on the poster. Eighteen other wood-warbler species migrate through the state, and five species are casual visitors to Illinois. Wood-warblers are vital components of Illinois’ ecosystems and their associated food webs.​

​Kingdom: Animalia - Animals are multicellular organisms that rely on other organisms for nourishment. There cells do not have cell walls. Most animals are capable of movement at least in some portion of their life cycle. Reproduction is generally sexual, but in some animals asexual reproduction may be utilized at certain times.
Phylum: Chordata - The Phylum Chordata contains the vertebrate animals. Mammals, birds, reptiles, amphibians and fishes are included in this phylum. These animals have a notochord at some point in their development. They have a tubular nerve cord along the back. Gill slits and a tail are present at some point in their life cycle. They have an internal skeleton.
Class: Aves - Birds are the only organisms with feathers. They are endotherms, maintaining a nearly constant body temperature. They have a hard bill but no teeth. A gizzard, which functions to grind food, is present in the digestive tract. Fertilization is internal. A nest is built in which the hard-shelled eggs are deposited and incubated.
Order: Passeriformes - These are small birds which have adaptations for holding on to thin twigs or stems. Three of the toes on each foot face forward and one backward to help it grasp and balance on small branches.

Family: Icteriidae
     yellow-breasted chat (Icteria virens)

Family: Parulidae - Warblers are small, vividly-colored (especially yellow) birds. There is much variation in the head and wing coloration of each species. Sexes are often different in appearance. The bill is narrow and pointed.
     ovenbird Seiurus aurocapilla
     worm-eating warbler Helmitheros vermivorum
     Louisiana waterthrush Parkesia motacilla
     northern waterthrush Parkesia noveboracensis *
     golden-winged warbler Vermivora chrysoptera *
     blue-winged warbler Vermivora cyanoptera
     black-and-white warbler Mniotilta varia
     prothonotary warbler Protonotaria citrea
     Swainson's warbler Limnothlypis swainsonii [state endangered]
     Tennessee warbler Leiothlypis peregrina *
     orange-crowned warbler Leiothlypis celata *
     Nashville warbler Leiothlypis ruficapilla *
     Connecticut warbler Oporornis agilis *
     mourning warbler Geothlypis philadelphia *
     Kentucky warbler Geothlypis formosa
     common yellowthroat Geothlypis trichas
     hooded warbler Setophaga citrina
     American redstart Setophaga ruticilla
     Kirtland's warbler Setophaga kirtlandii *
     Cape May warbler Setophaga tigrina *
     cerulean warbler Setophaga cerulea [state threatened]
     northern parula Setophaga americana
     magnolia warbler Setophaga magnolia *
     bay-breasted warbler Setophaga castanea *
     Blackburian warbler Setophaga fusca *
     yellow warbler Setophaga petechia
     chestnut-sided warbler Setophaga pensylvanica
     blackpoll warbler Setophaga striata *
     black-throated blue warbler Setophaga caerulescens *
     palm warbler Setophaga palmarum *
     pine warbler Setophaga pinus
     yellow-rumped warbler Setophaga coronata *
     yellow-throated warbler Setophaga dominica
     prairie warbler Setophaga discolor
     Townsend's warbler Setophaga townsendi *
     black-throated green warbler Setophaga virens *
     Canada warbler Cardellina canadensis *
     Wilson's warbler Cardellina pusilla *

Wood-warblers are migratory birds. They move seasonally between temperate regions of the Americas, where they breed, and tropical areas, where they spend the winter. The main reasons for this migration are that the insects they feed on cannot be found in great enough quantities for survival during the winter in the northern lands and that the amount of daylight in this season does not allow them time to forage enough daily to survive. They return to the northern regions annually for the large spaces and ample food supplies they require for nesting territories.

Wood-warblers depend on forests. Forests in both temperate and tropical climates have been greatly reduced and altered from their natural state. Forest fragmentation results when forests are cleared by humans and re-duced to small, isolated woodlots (fragments). Birds that require large tracts of contiguous forests may be unable to find suitable habitat to survive. Small woodlots allow many predators and nest parasites to have access to forest-interior bird species. In addition, much of this land is converted to long-term projects such as urban development, subdivisions, farms or other uses. Forest fragmentation and clearing also occur in the tropics as more space is needed for homes, agriculture and development. Loss of habitat along the migratory route can prohibit birds from obtaining the food and rest they need.

Pesticides and pollution can affect wood-warblers and their food sources. Many natural and humanmade obstacles cause problems for these birds during migration. Storms and strong winds can blow birds off course or provide headwinds that slow progress.

As of 2020, the Illinois Endangered Species Protection Board lists one wood-warbler species as endangered in the state and one species as threatened.

Endangered: Swainson’s warbler (Limnothlypis swainsonii) has always been uncommon in the state and is now extremely rare. Preservation of large tracts of bottomland forest and dense cane stands are critical for its survival in Illinois.

Threatened: The cerulean warbler (Setophaga cerulea) prefers to live in forests of more than 1,000 acres in size and is rarely found in forests smaller than 200 acres. This species was once abundant in the state, but loss of large tracts of forested habitat has been detrimental to it. Conservation actions needed to help preserve this species in Illinois include protection of mature deciduous forest, especially along streams, long-term timber management and maintenance of favored tree species, including oaks, sycamores, elms and chestnuts.

Birds and people both depend upon forest resources. In order to conserve wood-warbler populations, land use decisions regarding forests must take into account the impacts of those uses on people, birds and the forest. Migratory birds are a shared international resource. Their population declines illustrate the global effects of human actions.

The following ideas are practical steps that you can take to help conserve migratory bird species.

Participate in International Migratory Bird Day, held on the second Saturday in May, to educate others about migratory birds.

Write to state and national elected representatives to voice your concern over the plight of migratory birds.

Contact local environmental organizations or chapters of national organizations, such as the Illinois Audubon Society, to find out what they are doing about the issue.

Contact local representatives and parks personnel to learn about local land-use issues. Find out how you can learn about impor-tant local hearings, to provide public input on land-use decisions.

Conduct a school- or district-wide “Migratory Bird Day” to educate others in your school district about birds.

Take field trips to observe birds and contribute observations about bird populations to bird censuses or counts.

Plant native trees in appropriate places to increase bird habitat.

Take steps to reduce, reuse and recycle paper.

Plant a butterfly garden to provide habitat that supports insects that birds feed on.

Donate money to land preservation efforts.

Educate others about the dangers to birds from feral cats.

Leave snags and fallen trees in wood lots to provide habitat for birds and the insects they feed upon.

​More information about Illinois wood-warblers is available from the Illinois Department of Natural Resources (IDNR). The Division of Natural Heritage manages and monitors bird populations. Natural Heritage personnel also provide assistance to landowners regarding establishing and maintaining bird habitat. The IDNR Division of Education provides supplemental resources for educators to use, including the Illinois Common Birds activity book, (click here for the Spanish version), Illinois Birds resources trunk that is available for loan from more than 70 lending locations statewide, Field Trip Packs for early childhood educators and the Biodiversity of Illinois search page lists more than 1,000 species in the state. Wood Projects for Illinois Wildlife is an IDNR booklet that includes plans for nesting boxes that are used by some warblers. Publications are available through the publications page.

The Illinois Audubon Society’s mission is to promote the perpetuation and appreciation of the native flora and fauna of Illinois and the habitats that support them. Fundamental to this end are the control of pollution, the conservation of energy and all natural resources, a sound ecological relationship between human populations and their environments and the education and involvement of the public in such efforts.