fatalityCMR - capture-recapture software to correct raw counts of wildlife fatalities
using trial experiments for carcass detecition probability and
Contact Jim Hines if you would like to learn more about this project.
Many industrial and agricultural activities involve wildlife fatalities by
collision, poisoning or other involuntary harvest: wind turbines, highway
network, utility network, tall structures, pesticides, etc. Impacted wildlife
may benefit from official protection, including the requirement to monitor the
impact. Carcass counts can often be conducted to quantify the number of
fatalities, but they need to be corrected for carcass persistence time
(removal by scavengers and decay) and detection probability (searcher
efficiency). In this article we introduce a new piece of software that fits a
superpopulation capture-recapture model to raw count data. It uses trial data
to estimate detection and daily persistence probabilities. A recurrent issue
is that fatalities of rare, protected species are infrequent, in which case
the software offers the option to switch to an evidence of absence
mode, i.e., estimate the number of carcasses that may have been missed by
field crews. The software allows distinguishing between different turbine
types (e.g. different vegetation cover under turbines, or different technical
properties), as well between two carcass age-classes or states, with
transition between those classes (e.g, fresh and dry). There is a data
simulation capacity that may be used at the planning stage to optimize
sampling design. Resulting mortality estimates can be used 1) to quantify the
required amount of compensation, 2) inform mortality projections for proposed
development sites, and 3) inform decisions about management of existing sites.
14Nov2016 - fixed Max N estimate when MaxN < ad-hocN.
10Aug2015 - fixed var/cov when beta near zero, error in type2 est.
26Jun2015 - fixed computation of N* (correction for unequal time intervals)