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Wood Duck


Blanda Matzenbacher

on 1 May 2013

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Transcript of Wood Duck

Wood Duck (Aix sponsa) Population Trends on Portage Island by Blanda Matzenbacher Introduction surveys important for population status of species
hunting restrictions, conservation policies
history of surveys at Principia
continuation of wood duck survey on Portage Island
compare to previous data 2011 and 1978 Methods point-count method on Portage Island at sun rise
statistical analysis comparing 1978, 2011, 2012 google.maps.com Local population count in IL increasing North American Breeding Bird Trend Results, 1966-2010 North American Breeding Bird Trend Results, 1966-2010, Illinois Portage Island 65 in 8 days
9 per day 2011 74 in 12 days
6 per day 1978 1029 in 8 days
129 per day population dropped 93.7% from 1978 to 2012 on Portage Island
Tosto (2011) measured 94% P-values
2012 / 2011 - 0.516
not significant

2012 / 1978 - 0.0191
highly significant! When does migration begin and end?

Can there be a trend detected?

Are there alternative habitats for wood ducks? Research Questions Wood Duck (Aix sponsa) North American migratory species
three populations: Pacific, Atlantic, Central
Central population uses Mississippi flyway
roost in trees
return to same roosting grounds Why did wood ducks leave the Portage Island roosting ground? sensitive to habitat changes
rising water level - less mobility
low water level - no marsh
acorns not available
1993 flood caused hardwood tree tip overs in wetlands
mild winter
surrounding roosting and foraging areas preferred difficult to do a consistent survey with boat
no historic data on tree species, vegetation, topography of Portage Island Results might have missed migration numbers uncharacteristic due to environmental factors Portage Island not in favor When did migration start and end? beginning of October - December
Tosto (2011) did not miss migration Were 2011 numbers uncharacteristic? identical decrease in wood duck population
no trend detected 145 in 3 days, 49 ducks/day Difficulties Are their alternatives to Portage Island? Marais Temps Clair
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