I aim to understand how species respond to extreme variation in environmental conditions brought on by climate change by focusing on mountain chickadees (Poecile gambeli) across an elevation gradient at Sagehen Experimental Forest in the northern Sierra Nevada, USA. Mountain chickadees are year-round residents of montane coniferous forests and rely on invertebrates for food during their breeding season. In the northern Sierra Nevada, climatic swings result in unpredictably alternating years of deep snow, with stronger impacts at higher elevations, and drought, with stronger impacts at lower elevations. 

My lab’s long-term existing system of ca. 350 nest boxes across low elevation (range: 1965 m–2070 m) and high elevation (range: 2380 m–2590 m) sites results in approximately 100 active nests every year, allowing easy tracking of reproduction. All adult birds are tagged with passive integrated transponders (PIT tags) and tracked using radio frequency identification-equipped feeders and nest boxes. 

My lab has collected 12 years of continuous data on reproduction of tagged birds, allowing me to track the breeding behavior of the same individual birds across multiple years under different environmental conditions. I collect arthropod data from April - October annually using beating sheets to sample foliage-dwelling arthropods and Malaise traps to sample flying arthropods. I am also collecting nestling fecal samples for fecal DNA metabarcoding to document nestling diet and verify that my arthropod sampling methods are capturing arthropod groups relevant to chickadees. 

Considering the high frequency of extreme climate events at my study site, I will be able to compare mountain chickadee phenology and arthropod peaks and seasonal abundance across years of extreme environmental variation during my PhD. My work will provide critical insight into how resident montane species respond to climate change.