Spatial and temporal patterns in population change for Barn Swallow, from the North American Breeding Bird Survey #NABBS.
Increasing across most of its range until the early 1980s. Since then decreasing and most strongly in the north.
This change-point in the 1980s is common for most species of swallows, swifts, and nightjars in North America.
#BiologicalMonitoring #AerialInsectivore #BiodiversityLoss

Northern Cardinals decreased 1966-1979, then increased until 2005. They have been stable since 2005 (blue on map = increase, red = decrease). The increases have been at the northern and western edges of their range, and since 2005, they've been decreasing in the south.
#NABBS #BiologicalMonitoring #Birds #PopulationTrends #NorthernCardinal #NOCA

Pine Warblers increased across their range from 1966 - 2000 (blue regions on maps). Since then they've been fluctuating but overall relatively stable. That survey-wide stability is a composite of decreases in the south (red coloured regions in south) and ongoing increases in the north (blue coloured regions).
#NABBS #BiologicalMonitoring #Birds #PopulationTrends #PineWarbler