What is a Songbird?
Orioles, jays, warblers, swallows, robins, wrens, finches, and hundreds of other species make up this highly diverse group of birds. The changes of nature as winter evolves into spring, and the lengthening of day light, signal songbirds to begin confirming pair bonds and defending nesting territories. Thus, springtime brings a concert of songbird vocalists singing their repertoires in our woodlands, grasslands, mountains, wetlands, deserts, city parks and our own backyards.
Songbirds are members of the Order Passeriformes, more commonly known as passerines or “perching” birds because their feet (three toes forward and one backward) are adapted to gripping a perch. This order is further broken down into two suborders, the Oscines or true songbirds, and Suboscines, Tyrant flycatchers and their allies. Aside from having some anatomical differences from true songbirds, the song of Tyrant flycatchers (and allies) is innate i.e., their song has been genetically “hard-wired” in their brain enabling them to sing without ever hearing the adult song. Most songbirds must learn their songs from other birds. Photo (left, above) is a Western Kingbird.
Nearly half of all species in the world are passerines and of these, 4,600 are songbirds. In terms of population numbers, passerines are the dominant land birds on all continents occupying every type of habitat from forest to grassland. Most are migratory, traveling thousands of miles to and from their breeding grounds. They live in a wide variety of habitats. Some are adapted to withstand life in hot deserts, while others such as the Hoary Redpoll, can survive temperatures well below zero in the Arctic tundra. Nests of songbirds can be as simple as lining the inside of a tree cavity, crafted entirely with mud or as elaborate of those woven with grasses or moss and lichens (Bushtit nest, photo right).
Passerines have altricial young (photo left); born featherless, with eyes closed, and completely dependent on their parents for several days or more. Most passerines fledge the nest at 2-4 weeks of age. Some, like swallows, are able to fly immediately from the nest. Others, such as robins and jays, leave the nest before they are capable of full flight. For two to three weeks, until their wings and tail complete their development, they are learning the ways of the wild yet are still attended to by their parents. When young birds first leave their nest, this (fledgling) stage of development, is when they are most vulnerable to predators and other hazards.
Songbirds have many unique characteristics that set them apart from other species. They have a highly developed syrinx, or voice box, which enables them to produce a diversity of complex sounds. Some songbirds sing beautiful melodious songs, while others are capable of impersonating calls of other bird species. Birds that can mimic, such as crows, thrashers, and starlings, may reproduce human words and even non-natural sounds such as cell phone ring tones, car alarms, cats, and dogs. The most complicated songs are produced by thrashers, thrushes and wrens. The Brown Thrasher (photo right) may have over 2,000 unique sounds included in their vocal repertoire. Most songbird species have large brains relative to their small body size. It is believed that some of the most intelligent animals on earth, aside from humans, are members of the corvid family (jays, crows, and ravens). Recent studies published in the Proceedings of the National Academy of Sciences, indicates that overall brain size does not necessarily indicate level of intelligence. Rather, in songbirds, it is the size of the higher brain area (the area that controls the majority of cognitive and learning functions) in relation to lower regions (the area that controls motor functions) that predict ability for enhanced learning.
Common names of songbirds often describe their colorful plumage, the sounds they make, how they forage, or even the size of their bill: Indigo Bunting (photo left), Northern Mockingbird, Brown Creeper, and Black-headed Grosbeak. All passerines have 9-10 functional primaries and 12 tail feathers. The size of a North American songbird can vary from the largest (raven) weighing over 2.5 lbs and the smallest (kinglet) weighing 1/3 oz.
Songbirds exhibit the widest array of feeding types in any order of birds. They eat a variety of foods including seeds, nuts, berries, fruits, nectar, insects, invertebrates, amphibians, reptiles, other birds, and mammals. All songbirds, except some kinds of finches, feed insects to their young in the spring and summer. Insectivorous songbirds are highly beneficial to farmers and gardeners in that they can consume thousands of insects a day during nesting season.
Status and Conservation of Songbirds:
Many North American bird populations, including songbirds, have significantly decreased in number since 1967, according to surveys, reports, and scientific studies. “Common Birds in Decline,” a report by the National Audubon Society, shows that this reduction is due to several threats. Habitat loss and fragmentation due to human development are the primary factors for declining populations of migratory songbirds. This means that birds have fewer choices where to raise their young, and resources for food and shelter become so depleted that many birds are unable to survive winter conditions. Non-natural (domesticated) animals are taking an enormous toll. According to the American Bird Conservancy, “scientists now list invasive species, including cats, as the second most serious threat to bird populations worldwide.”
It is estimated that more than 85 percent of songbirds perish during migration. For hundreds of centuries they have survived in spite of extreme conditions along their journey. But in recent decades, the number of human-caused threats is increasing. Technological advances have resulted in the deaths of hundreds of millions of birds annually after striking windows, wind turbines, television and radio towers. The newest threat on the growing list, is solar plants that are incinerating birds in mid-air. Scientists consider birds as one of nature’s barometers. The affects of global warming, water pollutants, and air pollution, particularly acid rain are becoming more and more evident with the changes in movements of many species, as well as in their inability to learn their songs, and reproduce viable young. “Researchers worry that global warming may disrupt the precisely timed songbird migrations that coincide with the availability of food in spring and summer, or that changing temperatures may alter plant communities, making them unsuitable for some species of birds.” (Miyoko Chu, Songbird Journeys)
Western Kingbird: "Tyrannus-verticalis-001". Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Tyrannus-verticalis-001.jpg#mediaviewer/File:Tyrannus-verticalis-001.jpg
Bushtit nest: "Psaltriparus minimus 03647" by Walter Siegmund - Own work. Licensed under Creative Commons Attribution 2.5 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Psaltriparus_minimus_03647.JPG#mediaviewer/File:Psaltriparus_minimus_03647.JPG
Altricial chicks in nest: "Altricial chicks" by Qatar&Me from Doha, Qatar - http://www.flickr.com/photos/23780712@N05/2423653535. Licensed under Creative Commons Attribution 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Altricial_chicks.jpg#mediaviewer/File:Altricial_chicks.jpg
Brown Thrasher: "Toxostoma rufum -Garland, Texas, USA-8" by Manjith Kainickara from Dallas, Texas, USA - Brown ThrasherUploaded by snowmanradio. Licensed under Creative Commons Attribution-Share Alike 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Toxostoma_rufum_-Garland,_Texas,_USA-8.jpg#mediaviewer/File:Toxostoma_rufum_-Garland,_Texas,_USA-8.jpg
Indigo Bunting: "IndigoBuntingonPlant" by Kevin Bolton - A male in breeding plumage. Indigo Bunting.. Licensed under Creative Commons Attribution 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:IndigoBuntingonPlant.jpg#mediaviewer/File:IndigoBuntingonPlant.jpg