CLIMATE-DRIVEN BREEDING SHIFTS IN MIGRATORY BIRDS: A 20-YEAR FIELD STUDY

Abstract

 In the past two decades, the population of migratory birds has shifted significantly, in regard to their reproduction timing. This is largely due to the fact that the climate change is increasingly taking place.  This was a 20 years, field trial that observed >12 species encompassing numerous flyways and their arrival dates, nesting early commence dates as well as clutch sizes and fledging success, to understand the impacts of the local climatic changes in terms of temperature, rainfall, and growing degree days.  We found that, long-term data indicated that the first eggs were occurring earlier at a rate of 6.3 days per decade. It was directly associated with the beginning of spring temperatures (r = 0.78, p < 0.01).  Clutch size and hatching success simultaneously decreased significantly (though not by much on average) in species that breed higher latitudes. This implies that the latter is out of synch with regard to the time of the breeding and the prime food availability.  The most committed phenological practitioners to not alter, namely long distance migrants, were in the worst position to accommodate changing phenology.  According to satellite-based NDVI and habitat evaluation, importantly, fledging rates were reduced in association with inferior plant productivity of breeding spots.  Such findings indicate that the ecology of bird mating is Modifying largely due to both the direct thermal information and the indirect trophic dynamics.  This paper is made up of a mixture of ecological modelling, field based phenology and the perception of the stakeholders to provide us with an insight as to the level of migratory birds approachability to adapt to changing climatic environments as well as their scarcity.  According to our findings, it is necessary to take steps to preserve vulnerable species since we have to establish a conservation strategy based on climate projections as well as phenological limits.