Black Crappie (Pomoxis nigromaculatus) is a widespread introduced species in the Pacific Northwest; however, little is known about its impact on native fauna including predation of juvenile anadromous salmonids. We collected diet information on Black Crappie in the south end of Lake Washington near the outlet of the Cedar River (Renton, WA), a major spawning tributary for anadromous salmonids. Black Crappie were collected for 4 y (2022–2025) from mid-February through April to coincide with peak migration of juvenile anadromous salmonids. Roughly half of the Black Crappie had consumed salmonid fry, with Sockeye Salmon (Oncorhynchus nerka) representing 89% of the total salmonid weight and 98% of the observed number of salmonid fry. Predation of Sockeye Salmon fry was commonly observed during all 4 y and generally occurred throughout the sampling period. Juvenile salmonids represented about 20% of the diet (mean proportion by weight). Opossum Shrimp (Neomysis mercedis) was the principal prey item of Black Crappie. Other major prey types included aquatic insects, zooplankton, Longfin Smelt (Spirinchus thaleichthys), and sculpins (Cottus spp.). We also collected Black Crappie diet samples from other areas of the lower Lake Washington basin (March–June) and no juvenile salmonids were observed. Instead, their diet consisted largely of Opossum Shrimp and zooplankton. In summary, Black Crappie appears to be an important predator of Sockeye Salmon fry as they enter the lake. The current overlap between the distribution of Black Crappie and Sockeye Salmon nursery lakes is limited to a few lakes but could become more of a concern for fishery managers if Black Crappie expands their distribution to more northern lakes in the Pacific Northwest.
The hunting behavior of falcons, particularly when hunting shorebird prey species, has been investigated in numerous studies, most of which were conducted during nonbreeding periods. Relatively few studies of falcon hunting behavior, however, have been conducted during spring migration. Between 2006 and 2025, I observed hunting activity by Peregrine Falcons (Falco peregrinus) and Merlins (F. columbarius) during a long-term study of shorebird migration at Grays Harbor and Willapa Bay, Washington. On 80 of 267 field dates, I observed 146 instances of hunting activity, which I defined as hunting effort with or without a known ending, and including observations of falcons with prey even if the hunting flight was not observed. Hunting activity was observed by Merlins (13 instances) between 21 April and 10 May, and Peregrine Falcons (133 instances) between 7 April and 22 May, during the observation period. The median date of the last hunting activity by Peregrine Falcons across all years was 15 May. Prey were captured from single- or mixed-species flocks and included Red Knot (Calidris canutus), Sanderling (C. alba), Western Sandpiper (C. mauri), Dunlin (C. alpina), and Short-billed Dowitcher (Limnodromus griseus). Some shorebirds dived to or were knocked to water or mudflats by falcons; 8 of these shorebirds survived, whereas 6 were captured. I observed more hunting activity than expected at Willapa Bay and less than expected at Grays Harbor, perhaps because a Peregrine Falcon breeding territory at Grays Harbor was occupied in most years and the resident falcons may have excluded others from the area. The hunting success of Peregrine Falcons was 47% (39 successes in 83 hunting flights with known endings), and 43% (3 successes in 7 hunting flights) for Merlins. The success of Peregrine Falcons was comparable to that of other studies in Washington but higher than in most other studies globally; differences are largely due to different definitions of hunting behavior. Peregrine Falcons were challenged for possession of prey by other Peregrine Falcons 2 times and Bald Eagles 3 times. These data represent a baseline of predator-prey interactions between falcons and shorebirds in coastal Washington during spring migration. The magnitude and variation of predation risk along the migratory pathway is poorly understood and should be investigated more comprehensively.
The status and trend of wintering goose populations along the coast of the Pacific Northwest is relatively unstudied. We estimated the status and trends of 6 subspecies of white-cheeked geese wintering in Nestucca Valley, Oregon, USA. Surveys conducted from 2007 to 2019 revealed significant variability in weekly counts among subspecies and years. Dusky (Branta canadensis occidentalis) and Cackling (B. hutchinsii minima) Geese typically arrived by mid-October and stayed until mid-April, while Aleutian Geese showed lower autumn numbers but doubled in spring. Trends indicated a significant delay in Dusky Geese arrival in recent years, with departure dates remaining constant. Total goose use-days averaged 903,899, with notable declines over the period for Aleutian (B. h. leucopareia), Taverner's (B. h. taverneri)/Lesser (B. c. parvipes), and Western (B. c. moffitti) Geese. Supporting approximately 6000 geese daily, these results underscore the importance of Nestucca Bay National Wildlife Refuge and adjacent lands for wintering geese. These findings also highlight Nestucca Valley's role as a critical late-winter staging ground, particularly for Aleutian Geese, and emphasize that continued monitoring and adaptive management are essential to sustain these populations.
The resort community of Sunriver, Oregon, includes a 121 ha (300 ac) meadow that was used for cattle grazing for 20+ y before Sunriver began development in 1968. At the time of development, the meadow was partitioned into several fenced pastures that have been used by horses since 1968 (>50 y). Three sites within the “Great Meadow” of Sunriver with different grazing histories offered the opportunity to investigate the correlation between grazing history and occupancy level by Belding's Ground Squirrels (Urocitellus beldingi). In October and November 2019, we counted open squirrel burrows using six 20 × 20 m quadrats within each of the 3 study sites. The number of ground squirrel burrows was highest in the site that had heavy livestock use annually for the previous 50 y, intermediate in the site that had been grazed for 45 y followed by 5 y with livestock exclusion, and lowest in the site without livestock for 50 y. Vegetation total dry-weight biomass was lowest in the heavily grazed site and highest in the site with 5 y of livestock exclusion. It appears that heavy annual grazing resulted in increased occupancy by Belding's Ground Squirrels and reduced vegetative cover.
American Crows (Corvus brachyrhynchos) aggregate in the thousands on nocturnal roosting sites each night from early autumn through early spring. The impacts of such crow roosts on other wildlife species have not been thoroughly examined. Song Sparrows (Melospiza melodia morphna) hold territories year-round in Washington State, some of which are on crow roosting sites. Here, we tested the hypothesis that Song Sparrows holding territories on crow roosting sites would show season-dependent differences in aggression and vigilance behaviors. We exposed Song Sparrows on territories on crow roost and non-roost sites to playbacks of conspecific songs or distress calls during autumn (non-breeding), winter (non-breeding), and spring (early-breeding). In winter, Song Sparrows showed less territorial aggression on crow roost versus non-roost sites. Specifically, during song playback, they sang fewer songs, approached less closely to, spent less time within 1 m of, and displayed fewer movements toward the playback speaker than non-roost sparrows. Lower territorial aggression by roost sparrows during winter may be due to diminished territory quality when crow numbers are at their seasonal peak. In spring, Song Sparrows showed increased induced vigilance on crow roost versus non-roost sites. Specifically, during distress call playback, they sang fewer songs, spent more time within 5 m of, and made more movements toward the speaker. Increased vigilance by roost sparrows during early breeding may be a response to crows as potential nest predators. Our results suggest that crow roosts are associated with differences in Song Sparrow behaviors linked to survival and reproduction.
