Population status

Northern Harrier
(Circus cyaneus)

The Northern Harrier has a broad breeding distribution in Canada. About 60% of its breeding population is covered by the Breeding Bird Survey (BBS) despite low availability of its preferred habitat along BBS routes (e.g., upland graminoid, marsh wetlands). BBS results for Canada indicate the population has decreased by about 60% since 1970. Trends from the Bird Conservation Regions (BCRs) show moderate or large decreases, except the Atlantic Northern Forest which shows a moderate increase (results for all BCRs with reasonably reliable trends are displayed below). Results from the BBS for North America indicate a moderate decrease in continental populations of Northern Harrier.

Breeding Bird Survey (BBS) - Canadian analysis

Additional information on: Breeding Bird Survey (BBS) - Canadian analysis

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Table 1: Population trends by geographic area
Geographic area	Time Period ^{Table 1 - footnote 1}	Annual trend ^{Table 1 - footnote 2}	Intervals ^{Table 1 - footnote3}
Geographic area	Time Period ^{Table 1 - footnote 1}	Annual trend ^{Table 1 - footnote 2}	Lower	Upper
Canada Select to view graph of the geographic area: Canada 1970-2012; Breeding Bird Survey (BBS) - Canadian analysis	1970-2012	-2.2	-2.9	-1.5
Boreal Taiga Plains Select to view graph of the geographic area: Boreal Taiga Plains 1970-2012; Breeding Bird Survey (BBS) - Canadian analysis	1970-2012	-3.6	-5.4	-2.1
Prairie Potholes Select to view graph of the geographic area: Prairie Potholes 1970-2012; Breeding Bird Survey (BBS) - Canadian analysis	1970-2012	-2	-2.8	-1.3
Boreal Hardwood Transition Select to view graph of the geographic area: Boreal Hardwood Transition 1970-2012; Breeding Bird Survey (BBS) - Canadian analysis	1970-2012	-1.2	-2.8	0.4
Lower Great Lakes / St. Lawrence Plain Select to view graph of the geographic area: Lower Great Lakes / St. Lawrence Plain 1970-2012; Breeding Bird Survey (BBS) - Canadian analysis	1970-2012	-1.2	-2.5	0.2
Atlantic Northern Forest Select to view graph of the geographic area: Atlantic Northern Forest 1970-2012; Breeding Bird Survey (BBS) - Canadian analysis	1970-2012	1.6	0.2	3

Breeding Bird Survey in North America (BBS) - U.S. analyses

Additional information on: Breeding Bird Survey in North America (BBS) - U.S. analyses

View definitions of table column headings being used by: Breeding Bird Survey in North America (BBS) - U.S. analyses

Table 2: Population trends by geographic area
Geographic area	Time Period	Annual trend ^{Table 2 - footnote 1}	Limits
Geographic area	Time Period	Annual trend ^{Table 2 - footnote 1}	Lower	Upper
North America Select to view graph of the geographic area: North America 1966-2012; Breeding Bird Survey in North America (BBS) - U.S. analyses	1966-2012	-1	-1.6	-0.6

References

Smith, K.G., S.R. Wittenberg, R.B. Macwhirter, and K.L. Bildstein. 2011. Northern Harrier (Circus cyaneus), The Birds of North America Online (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca, New York. Smith, K.G., S.R. Wittenberg, R.B. Macwhirter, and K.L. Bildstein. 2011. Northern Harrier (Circus cyaneus), The Birds of North America Online (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca, New York. (Link)