Terms and Acronyms used in State of the Birds

A-C | D-G | H-L | M-P | Q-Z

A - C


Any member of the family Alcidae, including puffins and guillemots. These northern birds feed mainly on fish and squid, and fulfill the same ecological niche that penguins do in the Southern Hemisphere. 


see Breeding Bird Atlas below


see Breeding Bird Survey below

Breeding Bird Atlas (Atlas 1 and 2)

A Breeding Bird Atlas is a collection of data about all of the birds that breed in a particular state or region. The data is usually collected by ornithologists and other field researchers, along with many serious birders - citizen science at its best. The state is divided into 1,055 equal map blocks, and observers try to find all the breeding species in the block. Several years later the volunteers come back and do the same thing again. 
Mass Audubon collected data for Atlas 1 from 1974 - 1979. Read about BBA1
Mass Audubon collected data for Atlas 2 from 2007 - 2011. Read about BBA2.

Breeding Bird Survey (BBS):

The Breeding Bird Survey is a long-running project of the U.S. Geological Survey wherein volunteers walk or drive along a set route, stopping at pre-determined points to count all of the birds they hear or see for a certain amount of time.  These surveys are run along the same routes according to the same methods every year, so the data from many years of surveys are comparable. Find out more about the BBS.

Breeding Species:

A bird known to breed in Massachusetts, usually between the months of April and August, though some species (such as pigeons and crossbills) may breed at all months of the year.

Cavity Nester:

A bird that builds a nest inside a hollowed-out tree cavity is called a cavity nester. Many cavity nesters will accept artificial cavities, such as bird boxes or holes in the sides of old buildings. Birds such as Belted Kingfishers and Bank Swallows, which nest in earthen tunnels, are not cavity nesters.


see Christmas Bird Count below

Christmas Bird Count (CBC)

A National Audubon Society annual bird count that occurs from mid-December to early January every year. Read about the Christmas Bird Count.

Colonial Waterbird:

A group of very loosely related birds which breed along the coast in colonies, usually on offshore islands where mammal predators are not a threat. Cormorants, gulls, most herons, egrets and ibises all fall into this category.


A relationship between two organisms in which one benefits, while the other is unaffected.

D - G


The range over which a particular species can be found. Distribution and population are related, but not identical, and the relationship between them can be complex. Tens of thousands of pairs of Common Terns nest in Massachusetts, but they are restricted to a few breeding colony sites, so their distribution is small even though their population size is fairly large.

Early Successional Habitat:

The theory of succession posits that a cleared area will “succeed” through various stages over time, from grassland to shrubland to young forest to mature forest to old growth. Grasslands and shrublands are collectively called early successional habitats, and they usually persist in Massachusetts for less than 20 years before they transform into new forest.


A bird species that is found only in a particular region or habitat is said to be endemic to that region. For example, Fish Crows are endemic to the eastern United States.


Lasting for only a short period of time. Vernal pools are ephemeral in the sense that they dry up completely within a few months; natural grasslands in Massachusetts are ephemeral in the sense that they are completely overgrown with shrubs and young trees within a few years.


No longer seen locally, although the species is still found in other areas.


Birds belonging to the order Galliformes are sometimes referred to as gallinaceous birds. Examples include most upland game bird species such as turkeys, grouse, and pheasant.

Generalist Species:

In many ways the opposite of an obligate species, a generalist species can use a wide variety of habitats and can often exploit a correspondingly large variety of food sources.

Ground Nester:

A bird which consistently builds a nest on or very close to the ground. Most ground nesters depend on some combination of numbers, camouflage, and heavy undergrowth to hide their nests from ground predators.

H - L


The collection of living things and landform features (soils, topography, water, etc.) in which a particular species thrives. This may be as general as “wet areas” or as specific as “high-altitude bogs with extensive mats of sphagnum moss,” depending on the needs of the species.


Process through which birds of prey, such as falcons and eagles, can be raised in captivity and released into the wild.  Young birds are placed into specially-designed artificial nests in wild areas, where they are fed and cared for with minimal human contact until they learn to fly and depart on their own.


An irruptive species has a population which fluctuates quite severely from year to year, usually as a result of dependence on a similarly fluctuating food source. Evening Grosbeaks and box-elder seeds, Snowy Owls and lemmings, and Bay-breasted Warblers and spruce budworms are a few examples of irruptive predator-prey pairings.

Long-distance Migrant:

A species which regularly migrates from the United States or Canada to Mexico or Central or South America is a long-distance migrant.

M - P

Massachusetts Endangered Species Act (MESA)

Provides state protection to certain species deemed to be Threatened (T) or Endangered (E) by extinction at the state level, or to those deemed of Special Concern (SC). Read about the Massachusetts Endangered Species Act.

Massachusetts State Wildlife Action Plan (SWAP)

Produced by the state in 2005, SWAP identifies all MESA-listed species, plus an additional 34 bird species of conservation concern. Read about the State Wildlife Action Plan.


See Massachusetts Endangered Species Act above 

Obligate Species:

An obligate species depends entirely or almost entirely on one specific type of habitat. It cannot survive unless that habitat is available; thus, it is obligated to seek out and use such habitat.

Passage Migrant:

Birds which pause in Massachusetts to rest or feed but do not stay through either the breeding season or the winter. Many warblers and shorebirds follow this pattern. These birds are most commonly seen from February through April and then again from August through October.


A bird of the order Passeriformes. This order contains over half of all bird species. Commonly known as perching birds. 


Birds that live on the open sea, rather than around waters adjacent to land or around inland waters, such as shearwaters and petrels. It also refers to the habitat itself.


The number of individuals of a particular species that can be found in the state comprises its population. Also sometimes referred to as abundance.

Q - Z

Resident Species:

Individuals that remain in Massachusetts year-round. This is typical of game birds such as turkey and grouse, as well as some songbirds. 
Some short-distance migrants, such as chickadees, can be seen year-round. They are not considered residents, however, as the chickadees that breed here in the summer move south for the winter, and the chickadees we see in the winter have migrated here from their more northern breeding area.

Short-distance Migrant:

A species which regularly migrates but generally does so within the United States and Canada.Short-stopping:When a migration ends “short” of its traditional destination because conditions along the migration route are suitable for over-wintering or breeding.


A result that statistical analysis has determined unlikely to have occurred by random chance. (“Statistically significant” is also used.) A “significant decline” is a documented drop in bird populations which has been mathematically proven to be a genuine result rather than a random error.


Any of a group which includes many of the small passerine (perching) birds such as vireos, warblers, finches, blackbirds and sparrows.


See Massachusetts State Wildlife Action Plan above 


Plural of taxon, a group of organisms. For example, species are taxa.

Whispering Species:

In the context of State of the Birds, bird species that have decreased significantly in abundance but have not become significantly less widespread. (Also referred to as "whisperers.") These birds still seem to be common, but a more subtle examination reveals decreases in abundance, that, if sustained, could mean trouble for these species.

Wintering Species:

A bird that spends its winters in Massachusetts, usually between November and March.