DOI: 10.5061/dryad.8cz8w9gsr
title: Evaluating how management policies affect red wolf mortality and disappearance (1987-2020)

description: We analyzed data acquired from the USFWS Red Wolf Recovery Program
 (hereafter ‘Recovery Program’) on radio-marked (hereafter collared),
 monitored red wolves (i.e., within the NC recovery area). The Recovery
 Program data include the monitoring history for all collared and monitored
 adult red wolves released to the wild since the beginning of releases in
 1987 to March 1, 2020; n=526. The Recovery Program survival dataset
 contains the following individual covariates employed in our analyses:
 endpoint (i.e., final wolf fate by cause of death or disappearance
 [lost-to-follow-up, LTF]), capture date (beginning of monitoring), and
 date of endpoint (end of monitoring). The dataset also provided data on
 sex and other individual covariates not used for our study and hence not
 described. For recovered wolf carcasses, cause of death was estimated by
 USFWS using standard methods following necropsy and radiography. Agency
 removal occurred when a red wolf was captured and removed permanently
 (lethally or not) from the NC population, generally because the wolf was
 considered a problem animal by USFWS but also some wolves were removed to
 supplement other wild populations (n=5). The LTF endpoint occurred when a
 wolf in the wild disappeared from monitoring because the affixed
 radio-collar stopped functioning due to either mechanical/battery failure
 or tampering/destruction by external causes including humans. We
 reclassified the marked animals’ fates obtained from the Recovery Program
 survival data into the following mutually-exclusive endpoints, following
 previous studies: agency removals (lethal or not, by agency personnel;
 n=40, 7.6%), collision (trauma by vehicle(s); n=68, 12.9%), reported
 poached (n=150, 28.5%), nonhuman (unrelated to humans; e.g., disease,
 intraspecific strife, n=66, 12.5%), and unknown (unable to discern cause
 of death in necropsy; n=82, 15.6%). We include LTF (disappeared
 individuals; n=117, 22.2%) as one of multiple mutually-exclusive
 endpoints. We estimated the time between collaring (capture date) and
 endpoint in days (t) for each red wolf (n=526) in our dataset. We
 calculated time collared (t) differently for surviving, dead, removed to
 captivity and LTF endpoints, following previous studies. For our mortality
 endpoints, we estimated t for wolves monitored by telemetry until death.
 For wolves relocated to captivity, we used the date of final removal to
 captivity by agency action. For LTF wolves, we used the last date of
 telemetry contact. We censored any wolves who were alive at the end of our
 study period (March 1, 2020, n=3 wolves). In our study, we exploit the
 complementarity of both models: our joint stratified Cox model allowed us
 to test the hypothesis that our management covariates affected the rate of
 occurrence (i.e., hazard) of specific endpoints, and endpoint-specific FG
 models allowed us to test if and how much these same covariates affected
 the probability and incidence of said endpoints.
description: Data was collected by the US Fish and Wildlife Service Red Wolf
 Recovery Program between 1987-2020, and processed following available
 statistical code (see study SM).
description: Metadata provided only for attributes used (see abstract and
 study Methods).