OSU study: Warm waters delay murrelet fledging by 25%
Four years of video data show poor ocean conditions reduce food delivery and extend the time marbled murrelet chicks spend exposed to predators.
By Thabo Hoffmann ·
Researchers at Oregon State University analyzed 12,000 hours of video footage to determine how ocean temperatures affect marbled murrelet parenting. The team tracked feeding behaviors over four years, capturing data during both favorable and poor marine conditions. This long-term observation allowed them to isolate the specific impact of water temperature on chick development.
The study linked poor ocean conditions to warmer marine temperatures. These warmer waters appear to reduce the availability of Pacific sand lance, the primary food source for the small seabirds. Consequently, murrelet parents delivered fewer fish to their nests during these periods. This reduction in food supply directly impacted the growth rate of the offspring.
The data revealed that chicks in poor conditions took 25% longer to leave the nest compared to those in better conditions. This extended period on the branch increased their exposure to predators. Ravens and hawks posed a greater threat to the slower-developing birds. The findings raise specific concerns for a species already listed as threatened in California, Oregon, and Washington under the Endangered Species Act.
Jim Rivers, an associate professor of wildlife ecology and director of the Forest Animal Ecology Lab at OSU, noted that climate change is complicating population recovery. Warmer marine temperatures and stronger El Niño events are cited as factors harming the birds. Additionally, the degradation of old-growth conifer forests, which serve as nesting sites, contributes to the decline. The study provides concrete evidence of how marine changes translate into terrestrial survival challenges.
The research was presented as part of the "Think Out Loud" radio program. The show broadcasts live daily at noon with a rebroadcast at 8 p.m. Listeners can reach the program via Facebook, email, or voicemail to discuss the findings. The study offers a detailed look at the biological costs of a changing ocean for this protected species.
Source: KOPB-FM
