Population status

Williamson's Sapsucker
(Sphyrapicus thyroideus)

The Williamson's Sapsucker is too rare in Canada to be monitored by broad-scale population surveys such as the Breeding Bird Survey. However, BBS data from throughout North America suggest a relatively stable continental population relative to the early 1970s. Because Williamson's Sapsucker has such specialized habitat requirements, changes in that habitat have been used as a surrogate indicator of population change. In 2005, the population in a portion of one of the three main areas of occupancy in Canada was estimated to be decreasing based on the rate of change in its mature larch habitat (ECCC 2016c, COSEWIC 2005). However, a more rigorous estimate of change in the amount and quality of habitat in the area is required before a definitive estimate can be stated (ECCC 2016c). The population trends in the other two areas are unknown (ECCC 2016c). The objective outlined in the Recovery Strategy is to maintain the population at or above its current abundance and distribution (ECCC 2016c). Though data are insufficient to determine the change in population status relative to the early 1970s, the abundance of the small population of Williamson's Sapsucker is considered to be below the lowest acceptable level until it is de-listed under the Species At Risk Act.

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
Williamson's SapsuckerAbundance required for de-listing (SARA)Equal to goalNot applicable

Breeding Bird Survey (BBS) - Canadian analysis

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

Table 1: Population trends by geographic area
Geographic areaTime Period Table 1 - footnote 1 Annual trend Table 1 - footnote 2 Limits
LowerUpper
North America Select to view graph of the geographic area: North America 1970-2016; Breeding Bird Survey (BBS) - Canadian analysis1970-20160.6-0.82
 

References