There are three basic methods for estimating songbird numbers: encounter transects, point counts and spot mapping. Spot mapping is the most labour intensive and is only appropriate for relatively small areas when absolute abundance data are required. Depending on habitat type, spot mapping should usually not be used on areas larger than 20-60 ha. Encounter transects and point counts can cover much greater areas with far less effort. Encounter transects should theoretically sample the greatest number of birds, but point counts are more conducive to standardization. This is because variation in the speed travelled between any two transects, or even within transects, can contribute an undetectable bias; whereas with point counts, the effort spent actually counting birds can be precisely controlled by standardizing the duration of the counts. In addition, point counts are a more efficient method for obtaining large sample sizes than either encounter transects or spot mapping. For these reasons, point counts are recommended for estimating relative bird abundance, both for long term trends and for comparing abundances between habitats. Encounter transects can be useful for presence/not detected (possible) surveys, especially when combined with point counts. Spot mapping is recommended for determining absolute abundance within small areas. Distance methods should be considered as an alternative to spot mapping for absolute abundance estimates.
Songbirds belong to the Order Passeriformes and are also known as the perching birds or passerines (Gill 1990). They have unique adaptations such as distinctive feet (three toes pointed forward, one toe pointed backward), oil glands, and a reduced number of neck vertebrae. The group consists of five broad ecological forms: thrushes, flycatchers, creepers, warblers, and sparrows. For the purposes of this manual, they are classified as an inventory group as they can be surveyed using similar inventory methods. In British Columbia, passerines make up 40% of the avifauna ranging in size from the Raven to the Ruby-crowned Kinglet. Passerines can be found during the breeding season in almost all terrestrial habitats.
Table 1. Major taxonomic families of songbirds in British Columbia that can be inventoried with survey techniques recommended in this manual.
Family |
Common Name |
Tyrannidae |
Tyrant Flycatchers |
Vireonidae |
Vireos |
Corvidae |
Jays, Magpies and Crows |
Alaudidae |
Larks |
Paridae |
Titmice |
Aegithalidae |
Bushtits |
Sittidae |
Nuthatches |
Certhidae |
Creepers |
Troglodytidae |
Wrens |
Regulidae |
Kinglets |
Muscicapidae |
Bluebirds, Thrushes and Allies |
Mimidae |
Mockingbirds, Thrashers and Allies |
Sturnidae |
Starlings and Allies |
Motacillidae |
Wagtails and Pipits |
Bombycillidae |
Waxwings |
Parulida |
Wood Warblers |
Thraupidae |
Tanagers |
Emerizidae |
Buntings and New World Sparrows |
Cardinalidae |
Grosbeaks and Allies |
Icteridae |
Blackbirds |
Fringillidae |
Finches |
Passeridae |
Old World Sparrows |
Although songbirds are the subject of this manual, non-passerine species of birds will likely be encountered when using methods recommended here for songbirds. Observers recording songbird observations are encouraged to record all of the birds, passerine or otherwise, which they see or hear. Because not all of the province's bird species are the subject of inventory manuals like this one, records from songbird point counts may provide the only evidence of the presence of certain bird species (e.g., hummingbirds).