Dispersal behaviour and settlement in an invasive bird: dispersers prefer their natal habitat

Abstract

Habitat selection has profound consequences for individual fitness, but how do animals decide where to settle? The natal habitat preference induction (NHPI) hypothesis proposes that individuals choose habitats that exhibit similar environmental cues to those experienced in early life. In this study, we first examined juvenile movements and dispersal and then tested the NHPI hypothesis in the monk parakeet, Myiopsitta monachus, an invasive species that nests primarily in pine or palm trees in our study site. Juveniles were observed ranging extensively, but we found no relationship between ranging distances prior to dispersal and subsequent natal dispersal behaviour. As predicted by NHPI, we found that dispersed individuals displayed a significant preference for nesting in their natal tree type in their first year, irrespective of tree availability. The probability of changing tree type was not influenced by individual dispersal distance, the proportion of the natal tree type available or natal tree type.We found that adult birds undertaking breeding dispersal also showed a preference for the same tree type they dispersed from when making nest site selections, demonstrating that preferences can be maintained by adults during breeding dispersal movements. Finally, conspecific breeding success did not differ between palm and pine tree nests, and so did not provide a useful source of public information regarding the suitability of the two nesting substrates. These results contribute to our understanding of the drivers of habitat selection in both adults and juveniles and have implications for our understanding of dispersal patterns and range expansion in this worldwide invasive species.

Habitat selection has profound consequences for individual fitness, but how do animals decide where to settle? The natal habitat preference induction (NHPI) hypothesis proposes that individuals choose habitats that exhibit similar environmental cues to those experienced in early life. In this study, we first examined juvenile movements and dispersal and then tested the NHPI hypothesis in the monk parakeet, Myiopsitta monachus, an invasive species that nests primarily in pine or palm trees in our study site. Juveniles were observed ranging extensively, but we found no relationship between ranging distances prior to dispersal and subsequent natal dispersal behaviour. As predicted by NHPI, we found that dispersed individuals displayed a significant preference for nesting in their natal tree type in their first year, irrespective of tree availability. The probability of changing tree type was not influenced by individual dispersal distance, the proportion of the natal tree type available or natal tree type.We found that adult birds undertaking breeding dispersal also showed a preference for the same tree type they dispersed from when making nest site selections, demonstrating that preferences can be maintained by adults during breeding dispersal movements. Finally, conspecific breeding success did not differ between palm and pine tree nests, and so did not provide a useful source of public information regarding the suitability of the two nesting substrates. These results contribute to our understanding of the drivers of habitat selection in both adults and juveniles and have implications for our understanding of dispersal patterns and range expansion in this worldwide invasive species.

Habitat selection has profound consequences for individual fitness, but how do animals decide where to settle? The natal habitat preference induction (NHPI) hypothesis proposes that individuals choose habitats that exhibit similar environmental cues to those experienced in early life. In this study, we first examined juvenile movements and dispersal and then tested the NHPI hypothesis in the monk parakeet, Myiopsitta monachus, an invasive species that nests primarily in pine or palm trees in our study site. Juveniles were observed ranging extensively, but we found no relationship between ranging distances prior to dispersal and subsequent natal dispersal behaviour. As predicted by NHPI, we found that dispersed individuals displayed a significant preference for nesting in their natal tree type in their first year, irrespective of tree availability. The probability of changing tree type was not influenced by individual dispersal distance, the proportion of the natal tree type available or natal tree type.We found that adult birds undertaking breeding dispersal also showed a preference for the same tree type they dispersed from when making nest site selections, demonstrating that preferences can be maintained by adults during breeding dispersal movements. Finally, conspecific breeding success did not differ between palm and pine tree nests, and so did not provide a useful source of public information regarding the suitability of the two nesting substrates. These results contribute to our understanding of the drivers of habitat selection in both adults and juveniles and have implications for our understanding of dispersal patterns and range expansion in this worldwide invasive species.