# Field Methods Lab

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```					                 Field methods lab
• Auditory Point counts
– Simulated point counts using Bird Radio equipment
– Identify and map “birds” by song
– Need to know:
•   Wood Thrush
•   Black-throated Green Warbler
•   Winter Wren
– We will do three counts with increasing complexity
– You will compare your results with the true location and
species maps
– Consider factors that affect detection and identification on real
point counts
Field methods lab
• Visual point count – Independent double
observer method
– Pairs of observers scan for colored targets
representing different bird species
– Map the location of each target on your
datasheet
– Compare datasheets with your partner after
the count period
– Match observations in common
– For each “species” record the number of
individuals seen by each observer and the
number seen in common
SR
LR
SB
SR

LB
LB
Field methods lab
• Data Summary
– Each pair of observers will summarize their double observer
data on the data sheets provided and email them to Shiloh as
an Excel file by the end of day on Friday
• For each “species” in each habitat
– n1 (number of individuals seen by the first observer)
– n2 (number of individuals seen by the second observer)
– m2 (number of individuals seen in common)
– Shiloh will compile the data and post it online with an Excel
worksheet
– Use the Lincoln-Peterson equations in the worksheet to
estimate population size and detection probability for each
“species” in each habitat
Field methods lab

Example Data

Species 1
Habitat               n1          n2         m2             N    V(N)    p1     p2
Open Forest            8           6           4          11.6   3.36   0.67    0.5
Dense Forest           6           4           2         10.67   7.78    0.5   0.34
n1 = number of individuals seen by the first observer
n2 = number of individuals seen by the second observer
m2 = number of individuals seen by both observers
N = estimated population size
V(N) = variance of N
p1 = detection probability for observer 1
p2 = detection probability for observer 2
Field methods lab
• Write-up
- A summary of your results, including average
population estimate and detection probability for each
species from each habitat
- A comparison of your results to the true results, as
well as to other members of your lab
- A discussion of the factors that affected your ability to
detect "birds" on auditory and visual counts
- Your thoughts about other factors that may affect
detection probabilities on real point counts
- ~ 1-2 pages

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 views: 0 posted: 9/14/2012 language: English pages: 7