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Official List of the Birds of Alberta: Terms


Here is an explanation for the abbreviations and codes used in the Official List of the Birds of Alberta. 


Common and Scientific Names

The Common and Scientific Names, as well as the species sequence, follow the Check-list of North American Birds up to, and including, the 64rd supplement (AOU 1998, Chesser et al. 2023).


General Status

Br: a regular breeder in the province. These species do not stay year-round but rather come to the province in the spring to breed, leaving again in the fall. Abundance varies from abundant to scarce or local but all are findable when sought in the right habitat and season. Species with abundance modifiers are usually more difficult to find.

PR: a permanent resident. These species stay in the province year-round. They breed in the province and all or most individuals remain in the province for the winter months. Most of these species move only short distances from their breeding grounds.

Mig: these species only pass through the province. They do not breed or winter regularly in the province.       
Some species only pass through the province during the spring or fall migration, or abundance may differ between the two seasons. In this case, the following qualifiers apply:

SMig: spring migration;       
FMig: fall migration; F: fall.

WV: a winter visitor, individuals occurring during the winter period but not necessarily remaining all winter.

WR: a winter resident species, individuals arriving in the winter and remaining until they leave for the north in the spring.

Species in which the majority of individuals leave the province for the winter (though on the basis of some individuals remaining could be considered permanent residents) are coded as follows:

W: a species wintering in the province in some numbers but usually lower than during the breeding season.       
w: very few individuals winter in the province, species is irregular in winter, or does not winter on an annual basis. It should be noted that more species are attempting to winter in the province.

Acc: an accidental. These species have been documented on fewer than about fifteen occasions in the province. Many of these species are not likely to reoccur, or at best do only infrequently (Br indicates that the species has bred in the province, however).

V: a vagrant. These species have been documented more than about 30 times in the province, but fewer than 50 times. These species are of very irregular occurrence but most are likely to be reported again in the future. Br indicates that the species has bred in the province.

Acc/V: a species that, though it may have been reported more than about 15 times (often by reliable observers), is not well supported by documentation or material evidence. For accidental and vagrant species, we provide the year when that species' occurrence in the province was first confirmed.

Ext: extirpated. A species which no longer occurs in the province.

Int: introduced. A species introduced and now well established in the province.

Abundance qualifiers

vr: very rare, occurs in the province on a near annual basis but is extremely difficult to locate because of very low abundance, localized distribution or secretive nature. Extensive effort and luck is required for an observer to find one of these species in the province.

r: rare, occurs annually and is difficult to find, but numbers are higher than vr or it is less local in distribution.

s: scarce, may breed in low numbers, is difficult to locate because of its habits (secretive, nocturnal), or occupies habitats where it is difficult to observe or find.

l: local, a species which occupies only a very small percentage of available or suitable habitat and which is often known from only a few sites in the province.

u: uncommon.

Erratic: a species whose local abundance fluctuates widely from year to year.

Decl: a species known to be declining in abundance (question mark when it is suspected).     

Incr: a species known to be increasing in abundance (a question mark when it is suspected).


Findability Index

This numerical value captures the probability of an observer finding a particular species in the province during any given year or even a lifetime. It considers factors such as general abundance, provincial distribution, length of stay in the province, habits, and habitat preferences. It is similar to a coding system used currently by the American Birding Association (ABA).

1: These species are the most abundant and widespread birds in the province. They are present in the province for long periods of time, are conspicuous in behaviour, easily visible and observed, are often present in urban settings or easily attracted to feeders.

2: These species are generally less abundant and widespread, or their habits or the habitats which they occupy make them more difficult to find and observe.

3: These species are usually present on an annual basis in the province but are present in very low numbers or are very locally distributed. They may be in the province for only brief periods of time or their habits (secretive, nocturnal, inconspicuous) or the habitats which they occupy make them difficult to find. Some may be difficult to identify. It usually takes extensive effort on the part of the observer - as well as a bit of luck - to locate these species on an annual basis, or even in a lifetime.

Codes 1 to 3 constitute the regular avifauna of the province.

4: These species do not normally occur on an annual basis nor are they predictable as to locations where they might occur. These are wanderers that have occurred more than about 15 times in the past hundred years but fewer than 50 times. It is reasonable to assume that they will occur in the province irregularly in the future. These species are a lucky find by even the most experienced birders who spend much time looking for birds.

5: These species have been seen in the province on fewer than about 15 occasions and some may never be seen in the province again. These birds are finds of a lifetime and the probability of finding these in the province is extremely low to next to nil.

  6: These species are extirpated from the province, nearly extinct, or already extinct and therefore are not presently findable in the province.



This code derives from the present ABRC's practice of identifying the nature and quality of the best evidence for the occurrence of a rarity in the province, for records it has had a chance to adjudicate since it was created in 1995. This coding system is useful for producing provincial lists based on particular types of evidence, e.g., material evidence (Code 1).

Code 1. Records supported by material evidence, i.e., specimens, identifiable body parts, identifiable photographs or sound recordings, whose origin from within the borders of Alberta is in no doubt, that are accompanied by written reports of the circumstances of the observation.

Code 2. Sight records (without supporting material evidence) by multiple observers that are supported by independent written descriptions that leave no doubt as to the species' identity. A Code 1 or 2 sighting must receive four favourable votes and no more than one dissenting vote to be accepted.

Code 3. Sight records by one or more observers that are supported by a single written description that leaves no doubt as to species identity, and which receive five favourable votes and no dissenting vote. A Code 3 is the minimum for inclusion on the Official Provincial List.

Code 4. Sight records by single observers that receive four favourable votes and no more than one dissenting vote. For record adjudication purposes, such a record is acceptable, but does not pass the more stringent requirements for inclusion on the Official Provincial List. A list of Code 4 species may be published as an appendix to the Official List.


Literature Cited

American Ornithologists' Union (1998) Check-list of North American Birds, 7th ed. American Ornithologists' Union, Washington, D.C.

Chesser, R.T., S.M. Billerman, K.J. Burns, C. Cicero, J.L. Dunn, B.E. Hernández-Baños, R.A. Jiménez, A.W. Kratter, N.A. Mason, P.C. Rasmussen, J.V. Remsen, Jr., D.F. Stotz, and K. Winker. 2023. Sixty-fourth Supplement to the American Ornithological Society’s Check-list of North American Birds. Ornithology 140:1-11. DOI: 10.1093/ornithology/ukad023.