Interstate Island Habitat Restoration: Phase III – Long-Term Monitoring and Maintenance Plan Common Tern Monitoring & Migratory Shorebird Assessment Final Report

Abstract

The goal of the Interstate Island avian habitat restoration project was to restore and enhance critical breeding habitat for the Common Tern (Sterna hirundo) and Piping Plover (Charadrius melodus) in the St. Louis River Estuary. The primary objective of the habitat restoration was to maintain and increase the population of Common Terns breeding at the Interstate Island colony. To assess the effectiveness of the restoration, post-restoration field surveys were conducted to document the breeding status of Common Terns relative to pre-restoration averages. To document breeding population size and productivity, we followed the long-term monitoring protocol developed by the Wisconsin Department of Natural Resources (DNR), to ensure comparability between pre- and post-restoration monitoring. A secondary objective of the project was to document shorebird use of the island during migration to determine if this species group was utilizing the restored habitat. To meet this objective, researchers developed a shorebird monitoring protocol, conducted in-person surveys, and utilized remote camera traps to observe and quantify shorebird species diversity, abundance, and spatial and temporal use of Interstate Island. Based on post-restoration surveys, population targets are not currently being met for Common Tern, with the number of nesting pairs being at their lowest since the island was colonized. However, productivity was within the average range compared to pre-restoration numbers and the quality of the nesting habitat was greatly improved. If habitat quality is the primary factor limiting the size of the breeding population, we anticipate the restoration actions will likely result in an increase in breeding numbers but there may be a lag in response time. We also documented 18 shorebird species and 35 other avian species using the island during our surveys. Our results indicate that shorebirds as well as many other species of birds will readily use the newly restored habitat at Interstate Island, which is much needed in this important bird region. Continued monitoring and management will be necessary to determine long-term effects of restoration.