Visibility Bias and Disturbance of Waterfowl During Aerial Surveys

Andrew D. Gilbert, Heath M. Hagy, Christopher N. Jacques, Aaron P. Yetter

Research output: Contribution to conferencePaper

Abstract

Aerial waterfowl surveys have been conducted in the Illinois and Mississippi River floodplains since 1948. These traditional surveys provide an index of waterfowl population size and are used to track migration events, set harvest regulations, and for research purposes. New methods are being evaluated to estimate population size by randomizing survey locations and estimating count bias. We used double sampling to develop a correction factor for waterfowl estimates during fall aerial surveys. Immediately before an aerial survey, a ground observer surveyed waterfowl in predetermined locations from an elevated, unobstructed location where probability of detection was assumed to be 100%. Aerial counts were divided by ground counts for all common species and foraging guilds to determine visibility bias. Preliminary results indicate that mean detection rate for all waterfowl was 93% (SE=5%). Mean detection rate was 91% (SE=6%) for ducks, 96% (SE=7%) for dabbling ducks, 88% (SE=14%) for diving ducks, and 92% (SE=4%) for geese. Observers also documented disturbance to waterfowl caused by aerial surveys. Preliminary findings indicated 14% (SE=2%) of waterfowl, 10% (SE=1%) of ducks, 10% (SE=1%) of dabbling ducks, 6% (SE=1%) of diving ducks, and 21% (SE=3%) of geese exhibited negative responses (i.e., flew short distances, swam away, changed behavior significantly) to aerial surveys. Preliminary findings indicated that 4% (SE=1%) of waterfowl, 2% (SE=1%) of ducks, 1% (SE=1%) of dabbling ducks, 3% (SE=1%) of diving ducks, and 9% (SE=2%) of geese abandoned survey sites and did not return following aerial surveys. Traditional aerial surveys conducted in the Mississippi and Illinois River floodplains can be adjusted for visibility bias and compared with population estimates from randomized surveys to compare cost and time efficiency of aerial survey techniques.
Original languageEnglish (US)
StatePublished - 2018
Event2018 Midwest Fish and Wildlife Conference - Milwaukee, United States
Duration: Jan 28 2018Jan 31 2018
Conference number: 78

Conference

Conference2018 Midwest Fish and Wildlife Conference
CountryUnited States
CityMilwaukee
Period1/28/181/31/18

Fingerprint

aerial survey
waterfowl
visibility
disturbance
diving
population size
floodplain
guild
river
sampling
cost

Keywords

  • INHS

Cite this

Gilbert, A. D., Hagy, H. M., Jacques, C. N., & Yetter, A. P. (2018). Visibility Bias and Disturbance of Waterfowl During Aerial Surveys. Paper presented at 2018 Midwest Fish and Wildlife Conference, Milwaukee, United States.

Visibility Bias and Disturbance of Waterfowl During Aerial Surveys. / Gilbert, Andrew D.; Hagy, Heath M.; Jacques, Christopher N.; Yetter, Aaron P.

2018. Paper presented at 2018 Midwest Fish and Wildlife Conference, Milwaukee, United States.

Research output: Contribution to conferencePaper

Gilbert, AD, Hagy, HM, Jacques, CN & Yetter, AP 2018, 'Visibility Bias and Disturbance of Waterfowl During Aerial Surveys' Paper presented at 2018 Midwest Fish and Wildlife Conference, Milwaukee, United States, 1/28/18 - 1/31/18, .
Gilbert AD, Hagy HM, Jacques CN, Yetter AP. Visibility Bias and Disturbance of Waterfowl During Aerial Surveys. 2018. Paper presented at 2018 Midwest Fish and Wildlife Conference, Milwaukee, United States.
Gilbert, Andrew D. ; Hagy, Heath M. ; Jacques, Christopher N. ; Yetter, Aaron P. / Visibility Bias and Disturbance of Waterfowl During Aerial Surveys. Paper presented at 2018 Midwest Fish and Wildlife Conference, Milwaukee, United States.
@conference{e3f939c96b794e87847c59f382f68358,
title = "Visibility Bias and Disturbance of Waterfowl During Aerial Surveys",
abstract = "Aerial waterfowl surveys have been conducted in the Illinois and Mississippi River floodplains since 1948. These traditional surveys provide an index of waterfowl population size and are used to track migration events, set harvest regulations, and for research purposes. New methods are being evaluated to estimate population size by randomizing survey locations and estimating count bias. We used double sampling to develop a correction factor for waterfowl estimates during fall aerial surveys. Immediately before an aerial survey, a ground observer surveyed waterfowl in predetermined locations from an elevated, unobstructed location where probability of detection was assumed to be 100{\%}. Aerial counts were divided by ground counts for all common species and foraging guilds to determine visibility bias. Preliminary results indicate that mean detection rate for all waterfowl was 93{\%} (SE=5{\%}). Mean detection rate was 91{\%} (SE=6{\%}) for ducks, 96{\%} (SE=7{\%}) for dabbling ducks, 88{\%} (SE=14{\%}) for diving ducks, and 92{\%} (SE=4{\%}) for geese. Observers also documented disturbance to waterfowl caused by aerial surveys. Preliminary findings indicated 14{\%} (SE=2{\%}) of waterfowl, 10{\%} (SE=1{\%}) of ducks, 10{\%} (SE=1{\%}) of dabbling ducks, 6{\%} (SE=1{\%}) of diving ducks, and 21{\%} (SE=3{\%}) of geese exhibited negative responses (i.e., flew short distances, swam away, changed behavior significantly) to aerial surveys. Preliminary findings indicated that 4{\%} (SE=1{\%}) of waterfowl, 2{\%} (SE=1{\%}) of ducks, 1{\%} (SE=1{\%}) of dabbling ducks, 3{\%} (SE=1{\%}) of diving ducks, and 9{\%} (SE=2{\%}) of geese abandoned survey sites and did not return following aerial surveys. Traditional aerial surveys conducted in the Mississippi and Illinois River floodplains can be adjusted for visibility bias and compared with population estimates from randomized surveys to compare cost and time efficiency of aerial survey techniques.",
keywords = "INHS",
author = "Gilbert, {Andrew D.} and Hagy, {Heath M.} and Jacques, {Christopher N.} and Yetter, {Aaron P.}",
year = "2018",
language = "English (US)",
note = "2018 Midwest Fish and Wildlife Conference ; Conference date: 28-01-2018 Through 31-01-2018",

}

TY - CONF

T1 - Visibility Bias and Disturbance of Waterfowl During Aerial Surveys

AU - Gilbert, Andrew D.

AU - Hagy, Heath M.

AU - Jacques, Christopher N.

AU - Yetter, Aaron P.

PY - 2018

Y1 - 2018

N2 - Aerial waterfowl surveys have been conducted in the Illinois and Mississippi River floodplains since 1948. These traditional surveys provide an index of waterfowl population size and are used to track migration events, set harvest regulations, and for research purposes. New methods are being evaluated to estimate population size by randomizing survey locations and estimating count bias. We used double sampling to develop a correction factor for waterfowl estimates during fall aerial surveys. Immediately before an aerial survey, a ground observer surveyed waterfowl in predetermined locations from an elevated, unobstructed location where probability of detection was assumed to be 100%. Aerial counts were divided by ground counts for all common species and foraging guilds to determine visibility bias. Preliminary results indicate that mean detection rate for all waterfowl was 93% (SE=5%). Mean detection rate was 91% (SE=6%) for ducks, 96% (SE=7%) for dabbling ducks, 88% (SE=14%) for diving ducks, and 92% (SE=4%) for geese. Observers also documented disturbance to waterfowl caused by aerial surveys. Preliminary findings indicated 14% (SE=2%) of waterfowl, 10% (SE=1%) of ducks, 10% (SE=1%) of dabbling ducks, 6% (SE=1%) of diving ducks, and 21% (SE=3%) of geese exhibited negative responses (i.e., flew short distances, swam away, changed behavior significantly) to aerial surveys. Preliminary findings indicated that 4% (SE=1%) of waterfowl, 2% (SE=1%) of ducks, 1% (SE=1%) of dabbling ducks, 3% (SE=1%) of diving ducks, and 9% (SE=2%) of geese abandoned survey sites and did not return following aerial surveys. Traditional aerial surveys conducted in the Mississippi and Illinois River floodplains can be adjusted for visibility bias and compared with population estimates from randomized surveys to compare cost and time efficiency of aerial survey techniques.

AB - Aerial waterfowl surveys have been conducted in the Illinois and Mississippi River floodplains since 1948. These traditional surveys provide an index of waterfowl population size and are used to track migration events, set harvest regulations, and for research purposes. New methods are being evaluated to estimate population size by randomizing survey locations and estimating count bias. We used double sampling to develop a correction factor for waterfowl estimates during fall aerial surveys. Immediately before an aerial survey, a ground observer surveyed waterfowl in predetermined locations from an elevated, unobstructed location where probability of detection was assumed to be 100%. Aerial counts were divided by ground counts for all common species and foraging guilds to determine visibility bias. Preliminary results indicate that mean detection rate for all waterfowl was 93% (SE=5%). Mean detection rate was 91% (SE=6%) for ducks, 96% (SE=7%) for dabbling ducks, 88% (SE=14%) for diving ducks, and 92% (SE=4%) for geese. Observers also documented disturbance to waterfowl caused by aerial surveys. Preliminary findings indicated 14% (SE=2%) of waterfowl, 10% (SE=1%) of ducks, 10% (SE=1%) of dabbling ducks, 6% (SE=1%) of diving ducks, and 21% (SE=3%) of geese exhibited negative responses (i.e., flew short distances, swam away, changed behavior significantly) to aerial surveys. Preliminary findings indicated that 4% (SE=1%) of waterfowl, 2% (SE=1%) of ducks, 1% (SE=1%) of dabbling ducks, 3% (SE=1%) of diving ducks, and 9% (SE=2%) of geese abandoned survey sites and did not return following aerial surveys. Traditional aerial surveys conducted in the Mississippi and Illinois River floodplains can be adjusted for visibility bias and compared with population estimates from randomized surveys to compare cost and time efficiency of aerial survey techniques.

KW - INHS

M3 - Paper

ER -