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USGS - Glossary of Avian Terms Category: Agriculture and Industry > Glossary of Avian Terms Date & country: 30/06/2013, USA Words: 203

Habitat selection
preference for certain habitats (Ricklefs 1979:871).

Hatching success
percentage of eggs that hatch (Robinson and Rotenberry 1991:280) (syn. hatching rate [Mayfield 1975:459]).

Hatching-year
(HY) (1) a bird capable of sustained flight and known to have hatched during the calendar year in which it was banded (or seen) (Canadian Wildlife Service and U.S. Fish and Wildlife Service 1991:5-47); (2) a bird in first basic plumage in its first calendar year (Pyle et al. 1987:26-27).

Heterogeneity
the variety of qualities found in an environment (habitat patches) or a population (genotypic variation) (Ricklefs 1979:872).

Index
(1) the proportional relation of counts of objects or signs associated with a given species to counts of that species on a given area; (2) counts of individuals (e.g., at a feeding station) reflecting changes in relative abundance on a specified or local area (Ralph 1981:578).

Index method
a counting method involving sampling that yields measures of relative abundance rather than density values (Ralph 1981:578).

Indirect competition
the exploitation of a resource by one individual that reduces the availability of that resource to others (Ricklefs 1979:872).

Indirect effect
(1) the impact on a species caused by affecting the species' competitors, predators, or mutualists (Dunning et al. 1992:173); (2) the impact of toxic chemicals on a species by directly affecting interactions between species. Examples are disruptions in food resources or habitat changes that affect competitive interactions, biomagnification up the f...

Interference competition
competition in which one species prevents the other from having access to a limiting resource (Ehrlich and Roughgarden 1987:624) (cf Exploitation competition).

Interspecific competition
competition between individuals of different species (Ricklefs 1979:873).

Intraspecific competition
competition between individuals of the same species (Ricklefs 1979:873).

Key factor analysis
a statistical treatment of population data designed to identify factors most responsible for change in population size (Ricklefs 1979:873).

Landscape
the landforms of a region in the aggregate; the land surface and its associated habitats at scales of hectares to many square kilometers (for most vertebrates); a spatially heterogeneous area (Turner 1989:173); mosaic of habitat types occupying a spatial scale intermediate between an organism's normal home-range size and its regional distribution (...

Landscape change
alteration in the structure and function of the ecological mosaic of a landscape through time (Turner 1989:173).

Landscape complementation
changes in population caused by the relative distributions of habitat patches containing nonsubstitutable resources in a landscape. Example: increased populations in a portion of a landscape where foraging patches and roosting patches are adjacent, compared with parts of the landscape where these patches are isolated (Dunning et al. 1992:170-171) (...

Landscape composition
the relative amounts of habitat types contained within a landscape (Dunning et al. 1992:170).

Landscape ecology
field of study that considers the development and dynamics of spatial heterogeneity, interactions and exchanges across heterogeneous landscapes, the influences of spatial heterogeneity on biotic and abiotic processes, and the management of spatial heterogeneity (Turner 1989:172).

Landscape function
the interactions among the spatial elements, that is, the flow of energy, materials, and organisms among the component ecosystems (Turner 1989:173).

Landscape indexes
indexes of landscape structure (pattern), including richness, evenness, patchiness, diversity, dominance, contagion, edges, fractal dimension, nearest neighbor probability, and the size and distribution of patches (Turner 1989:177-178).

Landscape physiognomy
features associated with the physical layout of elements within a landscape (Dunning et al. 1992:170).

Landscape structure
spatial relationships between distinctive ecosystems, that is, the distribution of energy, materials, and species in relation to the sizes, shapes, numbers, kinds, and configurations of components (Turner 1989:173); composition and extent of different habitat types (landscape composition) and their spatial arrangement (landscape physiognomy) in a l...

Landscape supplementation
changes in populations caused by the distribution of habitat patches containing substitutable resources in a landscape. Example: increased population in a small patch found in a portion of the landscape where residents can easily forage in other nearby similar patches (Dunning et al. 1992:171-172) (see Landscape complementation).

Life form
characteristic structure of a plant or animal (Ricklefs 1979:873).

Life history
a system of interrelated adaptive traits forming a set of reproductive tactics (Stearns 1976:19).

Life table
a summary by age of the survivorship and fecundity in a population, usually of females (Ricklefs 1979:873).

Life zone
a more or less distinct belt of vegetation occurring within, and characteristic of, a particular range of latitude or elevation (Ricklefs 1979:873).

Limiting resource
a resource that is in short supply compared with the demand for it (Ehrlich and Roughgarden 1987:625).

Line transect
a sampling route, through a surveyed area, that is followed by an observer counting contacts over a measured distance (Ralph 1981:578).

Local extinction
disappearance of a population from a habitat patch or local area. Local extinctions can accumulate into regional extinctions and finally global extinction (adapted from Merriam and Wegner 1992).

MAPS
Monitoring Avian Productivity and Survivorship program, which utilizes constant-effort mist netting and banding and intensive point counts during the breeding season at a continent-wide network of stations. MAPS is coordinated by The Institute for Bird Populations (DeSante 1992).

Measurement bias
a systematic under- or overestimation of the true values due to a difference between the actual measurement and what one intends to measure (adapted from Gilbert 1987:11) (cf Statistical bias).

Mesic
moderately moist (Krebs 1985:724).

Metapopulation
a collection or set of local populations living where discrete patches of the area are habitable and the intervening regions are not (Gilpin 1987:127); basic demographic unit composed of a set of populations in different habitat patches linked by movement of individuals (Merriam and Wegner 1992:151).

Microhabitat
the particular parts of a habitat that an individual encounters in the course of its activities (Ricklefs 1979:874).

Minimum viable population
a threshold number of individuals that will ensure (with some probability level) that a population will persist in a viable state for a given interval of time (adapted from Gilpin and Soul 1986:19).

Monitoring
measuring population trends using any of various counting methods (Ralph et al. in press).

Morph
a specific form, shape, or structure (Ricklefs 1979:874).

Mortality
ratio of the number of deaths of individuals to the population, often described as a function of age; death rate (Ricklefs 1979:874).

Neotropical migrant
a migratory bird in the Neotropical faunal region. The Neotropical Migratory Bird Conservation Program focuses primarily on species that nest in the Nearctic faunal region and winter in the Neotropical region (Stangel 1992).

Nest parasitism
(1) expression used by some authors (e.g., Thomson 1964:594, Monroe 1991:225) for brood parasitism; (2) taking over nests of other species (Lanyon 1992:78).

Nest success
survival of eggs or nestlings (usually excluding those of brood parasites) (Mayfield 1975:459) (see Hatching success).

Net reproductive rate
the number of offspring that females are expected to bear on average during their lifetimes (Ricklefs 1979:875).

Niche
multidimensional utilization distribution, giving a population's use of resources ordered along resource axes (Schoener 1989:79).

Parameter
A statistical parameter is a numerical characteristic about the population of interest (Freedman et al. 1978:301); (2) A model parameter is a numerical quantity that mediates the relationships between variables in a model (Starfield and Bleloch 1986:4).

Partners in Flight
a Western Hemisphere program designed to conserve neotropical migratory birds and officially endorsed by numerous federal and state agencies and nongovernment organizations (National Fish and Wildlife Foundation 1992:1). Also known as Neotropical Migratory Bird Conservation Program.

Patch dynamics
the change in the distribution of habitat patches in a landscape generated by patterns of disturbance and subsequent patterns of vegetative succession (Pickett and Thompson 1978:29).

Pattern
a statement about relationships among several observations of nature. It connotes a particular configuration of properties of the system under investigation (Wiens 1989a:18).

Perennial
referring to an organism that lives for more than one year (Ricklefs 1979:876).

Phenotype
the way in which the genetic message of an individual is expressed in its morphology, physiology, and behavior (Brown and Gibson 1983:567).

Phylogenetic species concept
the idea that a species is the smallest diagnosable cluster of individual organisms within which there is a parental pattern of ancestry and descent (McKitrick and Zink 1988:2) (cf Biological species concept).

Physiognomy
the topography and other physical characteristics of a landform and its vegetation (Brown and Gibson 1983:568).

Point count method
count of contacts recorded by an observer from a fixed observation point and over a specified time interval: fixed distance (radius) point count is limited to individuals within a single fixed distance; variable distance (radius) point count is limited to individuals within distances varying according to species-characteristic detection distances (...

Point transect
a transect along which the point count method is used. No recordings are made between stations (as opposed to strip transects with continuous recordings) (Ralph 1981:578).

Polymorphism
occurrence of more than one distinct form of individuals in a population (Ricklefs 1979:877).

Population
a group of coexisting (conspecific) individuals that interbreed if they are sexually reproductive (Sinclair 1989).

Population viability analysis
(PVA) analysis that estimates minimum viable populations (Gilpin and Soul 1986:19) (syn. population vulnerability analysis).

Postfledging mortality
the death rate of young after fledging, calculated from the following: the fates of young birds after fledging (or hatching in the case of precocial young), when these fates can be observed directly; changes in the ratio between juvenile and adult birds in populations; and the number of surviving young needed to replace adult losses, when adult mor...

Precision
a quality, associated with a class of measurements, that refers to the way in which repeated observations conform to themselves (Marriott 1990:159).

Primary succession
the sequence of communities developing in a newly exposed site devoid of life (Ricklefs 1979:877).

Process
the operation of some factor or factors that produce a particular relationship among observations (Wiens 1989a:19).

Productivity
the number of young produced per pair of birds, or the reproductive performance of the population, estimated as the proportion of young in the total population just after the breeding season (Ricklefs 1972:417).

Rate of increase
a measurement of the change in numbers of a population. The finite, or geometric, rate of increase ( ) is the factor by which the size of a population changes over a specified period (Caughley 1977:51; Ricklefs 1979:871). The exponential rate (r) is the power to which e (the base of natural logarithms) is raised such that er = (Caughley (1977:52). ...

Recovery plan
a plan that details actions or conditions necessary to promote species recovery, that is, improvement in the status of species listed under the Endangered Species Act to the point at which listing is no longer appropriate. Plans are required for virtually all listed species (adapted from Rohlf 1989:87-89).

Recovery team
a group, established by the U.S. Fish and Wildlife Service (USFWS) or National Marine Fisheries Service (NMFS) (the agencies that share authority for listing species as endangered or threatened under the Endangered Species Act), that prepares a recovery plan for a species listed under the Endangered Species Act. The team usually consists of represe...

Recruitment
the addition of new individuals to a population by reproduction (Ricklefs 1979:878), commonly measured as the proportion of young in the population just before the breeding season (Ricklefs 1972:418).

Refugium
an area that remains unchanged while areas surrounding it change markedly; hence the area serves as a refuge for species requiring specific habitats (Brown and Gibson 1983:569).

Relative abundance
a percent measure or index of abundances of individuals of all species in a community (Ralph 1981:578) (syn. dominance [in Europe]; cf Index, Frequency, Density).

Remote sensing
the imaging of earth features from suborbital and orbital altitudes, using various wavelengths of the visible and invisible spectrum (Richason 1978:xi).

Resident
inhabiting a given locality throughout the year; sedentary (Welty 1975:463).

Resource
a substance or object required by an organism for normal maintenance, growth, and reproduction (Ricklefs 1979:878).

Restoration ecology
the re-creation of a natural or self-sustaining community or ecosystem (Jordan, Gilpin, and Aber 1987:331).

Second-year
(SY) a bird in its second calendar year of life (Pyle et al. 1987:27; Canadian Wildlife Service and U.S. Fish and Wildlife Service 1991:5-47).

Secondary succession
progression of communities in habitats where the climax community has been disturbed or removed entirely (Ricklefs 1979:878).

Sedentary
not migratory; see also resident (Welty 1975:46).

Sere
a series of stages of community change in a particular area leading toward a stable state (Ricklefs 1979:879).

Sink habitat
a habitat in which reproduction is insufficient to balance local mortality. The population can persist in the habitat only by being a net importer of individuals (adapted from Pulliam 1988:653-654).

Sink population
a population that occupies habitat types in which reproductive output is inadequate to maintain local population levels. The population may be replenished by emigrants from source populations (Wiens and Rotenberry 1981:531).

Source habitat
a habitat that is a net exporter of individuals (Pulliam 1988:654).

Source population
a population that occupies habitat suitable for reproduction, in which the output of offspring results in a population that exceeds the carrying capacity of the local habitat, promoting dispersal (adapted from Wiens and Rotenberry 1981:531).

Specialist
a species with narrow food preferences, habitat preferences, or both (after Ricklefs 1979:871) (see Generalist).

Species
a group of actually or potentially interbreeding populations that are reproductively isolated from all other kinds of organisms (Ricklefs 1979:880).

Species richness
the number of species in a given area (Ralph 1981:578).

Species-area relationship
a plot (often log-log) of the numbers of species of a particular taxon against area, such as islands or other biogeographic regions (Brown and Gibson 1983:570).

Spot-mapping method
a census procedure that plots on a map individuals seen or heard in a surveyed area. The survey is usually conducted over a period of days or weeks in a season, and individual territories or home ranges are then demarcated by examining the clusters of observations. Used in Breeding Bird Census (Ralph 1981:578) (syn. Territory-mapping).

Stable age distribution
the proportions of the population in different age classes when the rate of increase has converged to a constant (which depends on the fixed schedules of survival and fecundity). The ratios between the numbers in the age classes are constants (Caughley 1977:89).

Statistical bias
a difference between the expected value of an estimator and the population parameter being estimated (Gilbert 1987:12) (cf Measurement bias).

Stenotopic
found in only one or a relatively small number of habitats (MacArthur and Wilson 1967:191).

Stochastic
implies the presence of a random variable (Marriott 1990:197).

Stressor
any chemical, physical, or biological entity that can induce adverse effects on individuals, populations, communities, or ecosystems (Risk Assessment Forum 1992:1).

Strip transect method
a procedure using a strip of land, or water, of fixed direction that is sampled visually and/or aurally by an observer. Counts may be one of the following: fixed distance (width) counts limited to a strip of set width for all or specially chosen species; variable distance (width) counts, with different, species-specific widths that are determined t...

Subclimax
a stage of succession along a sere prevented from progressing to the climatic climax (i.e., the steady-state community characteristic of a particular climate) by fire, grazing, and similar factors (Ricklefs 1979:880).

Subspecies
subpopulations within a species that are distinguishable by morphological characteristics and, sometimes, by physiological or behavioral characteristics (Ricklefs 1979:880) (syn. race).

Succession
replacement of populations in a habitat through a regular progression to a stable state (climax) (Ricklefs 1979:880).

Survey
an enumeration or index of the number of individuals in an area from which inferences about the population can be made (Ralph 1981:578) (cf Census, Count).

Survival
the proportion of newborn individuals alive at a given age (Ricklefs 1979:880).

Sympatric
occurring in the same place, usually referring to areas of overlap in species distributions (Ricklefs 1979:880).

Territory
any area defended by one or more individuals against intrusion by others of the same or different species (Ricklefs 1979:881) (cf Home range).

Third-year
(TY) a bird in its third calendar year of life (Pyle et al. 1987:27).

Transect
a cross section of an area along which the observer moves in a given direction (Ralph 1981:578) (see Line transect, Point transect, Strip transect method).

Trophic
pertaining to food or nutrition (Ricklefs 1979:881).