Acoustic Activity as a Low Cost and Scalable Index of Seabird Colony Size: An Example with Forster's Terns (S. fosterii)

摘要: Although wildlife conservation actions have increased globally in both number and complexity, the dearth of scalable, cost-effective monitoring hampers effective intervention to understand efficacy. Automated sensors computer aided analysis expanded tools available for monitoring. For threatened elusive seabirds, acoustic presents a cost-effective, scalable alternative traditional methods that are limited by remote or inaccessible locations requiring skilled field personnel. A key assumption population trends acoustically is measures activity correlated with relative nesting abundance seabirds at colony sites. Here we tested efficacy as an index seabird colonies. Sensors recorded ambient noise Forster's Tern (Sterna forsteri) breeding colonies San Francisco Bay two seasons. We used automated method (spectrogram cross-correlation) detect count tern advertisement calls from recordings. calculated mean seasonal call rate compared it active nest Our results show was reliable size among sites accurate change between years (adj. R2=0.94, n=5, p<.01). Acoustic strong enough differences anticipated actions. more precise when comparing within years, than different sites, likely due sound environments small islands. Quantifying relationship fundamental step designing programs monitor effectiveness other vocalizing wildlife.