Pollen analysis as a tool to advance avian research and inform conservation strategies

Abstract

Ornithologists use many methods to advance understanding of birds and inform conservation strategies. These include field methods (e.g. censusing, ringing), laboratory analysis (e.g. molecular taxonomy, microbiology) and computational approaches (e.g. population modelling, habitat suitability mapping). Indirect metrics can also be important: for example, ptilochronology as a proxy for food availability and dominance hierarchies, stable isotopes as a proxy for diet and first egg dates as a proxy for phenological responses to climate change. Recently, the potential to use palynology – the study of pollen and spores – in ecology has become increasingly recognized, but there has been no specific appraisal of the utility of palynology in ornithology. In this scoping review, we synthesize research undertaken over 70 years across all seven continents covering the many diverse ways in which studying pollen associated with birds can advance ornithological understanding and inform conservation strategies. We critique the use of palynology both directly and as a proxy to study avian habitat use, migration ecology, diet and feeding strategies, and population dynamics, offering constructive suggestions for future research at the end of each thematic section. We also explore the potential for analysing pollen on birds (or within avian deposits such as guano) to answer wider questions, especially in relation to pollination and environmental reconstruction, thereby offering cross-disciplinary collaborative research ideas. We conclude that the potential for uniting ornithology and palynology within the research and conservation contexts is as extensive as it is exciting and urge avian biologists to think broadly about new opportunities.