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US Fish & Wildlife Service FieldNotes

Yellow-billed Cuckoos Pairs Increase on San Bernardino NWR

Region 2, July 21, 2013
Yellow-billed cuckoo in cottonwood.
Yellow-billed cuckoo in cottonwood. - Photo Credit: n/a

This year marks the seventh year that the San Bernardino National Wildlife Refuge has been conducting yellow-billed cuckoo monitoring. The cuckoo, a candidate species for listing under the Endangered Species Act, has seen its habitat decline in both its wintering and breeding habitats. Loss of its prey base has become an increased pressure on the cuckoo as well, with the use of pesticides destroying populations of tent caterpillars that are the main food source for cuckoos in the southwest. In 2007, refuge staff decided it would be beneficial in management of the species to begin surveys to determine the breeding population of the cuckoo on the refuge. Since the inception of the survey on the refuge, breeding pairs have ranged between possibly three pairs up to seven. The lowest year for breeding pairs was in 2011, where weather and spring wildfires were believed to have impacted migration and nesting of many avian species in the area. This year’s count had possibly five breeding pairs occupying the two riparian corridors on the refuge.

Contact Info: Christopher Lohrengel, 520-364-2104 x.106, chris_lohrengel@fws.gov