The abundance of bank swallow (Riparia riparia) nest holes within cliff and bank habitats along PEI National Park coastline is monitored. Previously, large historical colonies were surveyed annually, and every five years a complete census of the entire park shoreline was completed. As of 2010, a complete census is done annually along the coastline of PEI National Park following the breeding season. Nest holes are counted along the coast throughout PEI National Park by multiple observers. Counts are averaged annually to estimate nest hole abundance. Monitoring bank swallow nest hole abundance will determine if, based on historical records, the population size is within the expected range, or if it is increasing or decreasing over time.