Altering breeding behavior with age may help birds reduce breeding costs and enhance reproductive success in more experienced breeders. The age of the parents attending a nest affects a variety of breeding and parental behaviors as demonstrated in a wide range of species. However, trends appear to be inconsistent, which may be due in part to the logistical difficulties of studying free-ranging populations of identified and known-aged individuals. To further examine how age may influence reproductive behaviors, we examined nest construction, location, and fate in a population of well characterized, known-aged field sparrows (Spizella pusilla) on Maryland’s Eastern Shore. This color-banded population has been the subject of ongoing research since 2014 and is a common species found in mixed grass-shrub-edge habitats around the region.
Results/Conclusions
In our population, parent age did not appear to affect overall nest success or nest construction. However, characteristics of the nest itself influenced whether a nest failed or produced fledglings. These findings suggest that field sparrow breeding success may be more strongly influenced by factors attributed to the nest microhabitat and surrounding environment as a whole and less so the intrinsic factors attributed to the parents themselves. These findings suggest that habitat management may be an effective recovery technique for declining field sparrow populations and grassland bird species in general.