Comparison of Ground and Helicopter Surveys for Breeding Waterfowl in New Jersey

Abstract

ABSTRACTNew Jersey has participated in the Atlantic Flyway Breeding Waterfowl Survey by conducting ground surveys in the salt marsh strata, which are important for breeding waterfowl, particularly American black ducks (Anas rubripes). Ground surveys in salt marshes are time‐intensive, tide dependent, costly, and take several days to complete. We investigated the use of helicopters and compared the results of mallard (Anas platyrhnchos), black duck, and Canada goose (Branta canadensis) estimates to ground surveys. Expected mean point estimates for all species were consistently higher during ground than helicopter surveys. Expected mean point estimates were higher during both ground and helicopter surveys at twilight than at midday for Canada geese and black ducks, whereas mallard observations were higher during midday than twilight for both survey methods. We found no differences in results from helicopter surveys conducted at high versus low tide. Although helicopter contracts are expensive, ground surveys took 8.5 times more staff time to complete, resulting in similar cost between survey platforms. Helicopters provide an alternative for ground surveys in salt marshes of the Atlantic Flyway, and we provide recommendations to develop visibility correction factors for different species groupings to account for visibility bias associated with helicopter observations. © 2021 The Wildlife Society.