PERSISTENT ABUNDANCE OF SHOREBIRDS AND RAPTORS ON COASTAL WASHINGTON BEACHES AMID RISING RECREATION, 1983–2021.

We used count data from 158 surveys conducted at 3 beaches (Ocean Shores, Grayland Beach, Long Beach) in coastal Washington, to estimate annual and seasonal trends in human activity (2000 to 2021) and the abundance of shorebirds and raptors (1983 to 2021). Human activity, including vehicles, people (walkers), and dogs, was a persistent feature at all 3 beaches, and observed during >90% of all surveys. Human activities at all 3 beaches showed a consistent seasonal pattern, with high numbers during the late summer-autumn months and spring, and lowest numbers in mid-winter. Numbers of people on all 3 beaches increased from 2000 to 2021, with substantial rates of percent change over the 21-y study period: 128% at Grayland Beach, 191% at Ocean Shores, and 242% at Long Beach. Significant declines were observed for some shorebirds, including Western Sandpiper (Calidris mauri) and dowitchers (Limnodromus spp.), and increases were noted in others, including Snowy Plover (Charadrius nivosus) and Least Sandpiper (Calidris minutilla). There were increases in the abundance of 2 raptors, the Peregrine Falcon (Falco peregrinus) and particularly the Bald Eagle (Haliaeetus leucocephalus), which were essentially absent in the 1980s. At the beach level, we found significant negative correlations between the number of people and number of birds, including Least Sandpiper, Western Sandpiper, Bald Eagle, Merlin (Falco columbarius), and Peregrine Falcon. The existence of large numbers of shorebirds roosting on the coastal beaches and the general lack of strong downward trends despite the presence of substantial and increasing human activity suggests a certain level of habituation to the level of activity noted during the study period. Changes in behavior and the potential for physiological costs of disturbance should be investigated at finer spatial scales. [ABSTRACT FROM AUTHOR]