Holding steady: Little change in intensity or timing of bird migration over the Gulf of Mexico.

摘要: Quantifying the timing and intensity of migratory movements is imperative for understanding impacts changing landscapes climates on bird populations. Billions birds migrate in Western Hemisphere, but accurately estimating population size one species, let alone hundreds, presents numerous obstacles. Here, we quantify timing, intensity, distribution migration through largest corridors Gulf Mexico (the Gulf). We further assess whether there have been changes or Gulf. To achieve this, integrate citizen science (eBird) observations with 21 years weather surveillance radar data (1995-2015). predicted no change a decline across time series. estimate that an average 2.1 billion pass this region each spring en route to Nearctic breeding grounds. Annually, half these individuals just 18 days, between April 19 May 7. The western showed mean rate passage 5.4 times higher than central eastern regions. did not detect overall annual numbers migrants (2007-2015) peak However, found earliest seasonal occurred significantly earlier over (1.6 days decade-1 ). Additionally, body mass distance explained magnitude phenological changes, most rapid advances occurring assemblage larger-bodied shorter-distance migrants. Our results provide baseline information can be used advance our developing implications climate change, urbanization, energy development populations North America.