Productivity of Species of Concern – Least Tern and Common Tern on Poplar Island
This project aims to understand the factors driving breeding success of multiple waterbird species, with special emphasis on Least and Common Terns (two species of concern) on Poplar Island Environmental Restoration Project.
The Poplar Island Environmental Restoration Project (PIERP) has proven very successful at providing breeding habitat for colonially nesting waterbirds in the Chesapeake Bay, with USGS scientists playing an active role in evaluating use of this site ever since the pre-construction monitoring in 1996. However, concern has been raised over productivity of two important tern species that have colonized the island: the Maryland state-listed Least Tern (Sternula antillarum) and Common Tern (Sterna hirundo). Over the 21 year (and continuing) monitoring period at PIERP (beginning 2002), hatching and fledging success of these species has been variable, believed to be linked with natural stressors including avian and mammalian predators and severe weather events.
Productivity estimates such as hatching success (the number of nests in a sample that successfully hatch at least one egg) and fledging success (the number of chicks in a sample that survive to fledging) can be difficult to obtain, especially as chicks remain well-hidden after hatching. In 2013, USGS began a pilot project to improve estimates of hatching and fledging success for least and common terns on PIERP. Since this time, we have increased colony counts during the nesting season and added a mark-resight study to estimate fledging success for these species. Hatchlings are banded with official USGS metal bands on one leg and plastic field readable (PFR) bands on the other. Intensive resighting efforts are employed using a high-powered spotting scope to “recapture” individuals by reading the code on the PFR (such as A03 shown on the banded tern chick) and modeling detections to obtain estimates of survival. USGS scientists share their findings with collaborators on site to guide management activities and habitat design, while also exploring the broader ecology of these species. Concurrently, we continue to assess trends in the productivity of other species of concern breeding at PIERP, continuously testing emerging technologies that may help us address the challenges associated with the unique habitat types of each species.
Although resighting efforts require large numbers of person-viewing-hours, our work has shown success with improved estimates of survival. USGS works in close cooperation with US Fish & Wildlife Service, and benefits from additional help from qualified students, volunteers, and interns. The study will continue as PIERP continues to evolve, helping to understand how restoration efforts impact tern success.
This project aims to understand the factors driving breeding success of multiple waterbird species, with special emphasis on Least and Common Terns (two species of concern) on Poplar Island Environmental Restoration Project.
The Poplar Island Environmental Restoration Project (PIERP) has proven very successful at providing breeding habitat for colonially nesting waterbirds in the Chesapeake Bay, with USGS scientists playing an active role in evaluating use of this site ever since the pre-construction monitoring in 1996. However, concern has been raised over productivity of two important tern species that have colonized the island: the Maryland state-listed Least Tern (Sternula antillarum) and Common Tern (Sterna hirundo). Over the 21 year (and continuing) monitoring period at PIERP (beginning 2002), hatching and fledging success of these species has been variable, believed to be linked with natural stressors including avian and mammalian predators and severe weather events.
Productivity estimates such as hatching success (the number of nests in a sample that successfully hatch at least one egg) and fledging success (the number of chicks in a sample that survive to fledging) can be difficult to obtain, especially as chicks remain well-hidden after hatching. In 2013, USGS began a pilot project to improve estimates of hatching and fledging success for least and common terns on PIERP. Since this time, we have increased colony counts during the nesting season and added a mark-resight study to estimate fledging success for these species. Hatchlings are banded with official USGS metal bands on one leg and plastic field readable (PFR) bands on the other. Intensive resighting efforts are employed using a high-powered spotting scope to “recapture” individuals by reading the code on the PFR (such as A03 shown on the banded tern chick) and modeling detections to obtain estimates of survival. USGS scientists share their findings with collaborators on site to guide management activities and habitat design, while also exploring the broader ecology of these species. Concurrently, we continue to assess trends in the productivity of other species of concern breeding at PIERP, continuously testing emerging technologies that may help us address the challenges associated with the unique habitat types of each species.
Although resighting efforts require large numbers of person-viewing-hours, our work has shown success with improved estimates of survival. USGS works in close cooperation with US Fish & Wildlife Service, and benefits from additional help from qualified students, volunteers, and interns. The study will continue as PIERP continues to evolve, helping to understand how restoration efforts impact tern success.