EFFECTS OF IMPERFECT DETECTABILITY ON INFERENCES FROM AVIAN MONITORING

Ph.D. ASSISTANTSHIP in WILDLIFE ECOLOGY AND MANAGEMENT or CONSERVATION 
BIOLOGY 
Minnesota Cooperative Fish and Wildlife Research Unit 
University of Minnesota, St. Paul, Minnesota 

PROJECT DESCRIPTION: The value of bird monitoring has come under 
increasing scrutiny recently due to concerns about imperfect 
detectability.  In particular, because the probability of detecting a bird 
in the area surveyed often is less than one, counts are indices of 
abundance, rather than actual estimates of abundance.  Although a variety 
of methods that attempt to adjust counts for imperfect detectability have 
been advanced, questions arise about the applicability of the methods in 
extensive multispecies surveys.  A critical question is the extent to 
which estimates of population change are affected by imperfect 
detectability and whether or not suggested adjustment methods offer 
improved results worthy of the additional effort.  The objective of the 
proposed study is to evaluate the influence of imperfect detectability on 
inferences about population changes.   

The student is expected to simulate a wide variety of conditions involving 
detectability (both availability and perceptibility) and determine how 
inferences about trends would be affected.  Detectability will be varied 
in realistic ways, as indicated by field observations and controlled 
studies.  Simulated results will be adjusted for detectability in 
accordance with suggested procedures (various distance sampling, 
multiple-observer, and time-to-detection methods).  As necessary, field 
studies will be conducted to determine how detectability is affected by 
abundance and variety of birds and other features. 

REQUISITES: M.S. or M.A. in a scientific or mathematical field. 
(Alternatively, a B.A. or B.S. along with strong evidence that the student 
could successfully complete a Ph.D. program.) Quantitative and 
computational skills; an interest in avian biology and conservation; 
ability to work with diverse project cooperators; ability to help design 
and conduct simulation studies and field research; and meet or exceed 
program entry requirements in Natural Resources Science and Management 
(Wildlife Ecology and Management track) or Conservation Biology at the 
University of Minnesota. 

DESIRED EXPERIENCE: Previous field work with or surveys of birds, 
demonstrated quantitative and data analysis skills, and previous 
peer-reviewed publications. 

DURATION: As soon as suitable candidate is found, continuing for three 
years. 

STIPEND: About $18,800 per year, plus health insurance and tuition waiver 

CONTACT:         
Dr. Douglas H. Johnson 
Fisheries, Wildlife, and Conservation Biology 
200 Hodson Hall 
1980 Folwell Avenue 
St. Paul, MN  55108 
[email protected] 
612-624-4716 

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