MPG Black Bear research encounter histories

Wildlife pedigrees provide insights into ecological and evolutionary
processes. DNA obtained from non-invasively collected hair is often used
to determine individual identities for pedigrees and other genetic
analyses. However, detection rates associated with some non-invasive DNA
studies can be relatively low and genetic data do not provide information
on individual birth year. Supplementing hair DNA stations with video
cameras should increase individual detection rate, assuming accurate
identification of individuals via video data. Video data can also provide
birth year information for individuals captured as young of the year,
which can enrich population-level pedigrees. We placed video cameras at
hair stations and combined genetic and video data to reconstruct an
age-specific, population-level pedigree of wild black bears during
2010-2020. Combining individual birth year with mother-offspring
relatedness, we also estimated litter size, interlitter interval,
primiparity, and fecundity. We used the Cormack-Jolly-Seber model in
Program Mark to evaluate the effect of maternal identity on offspring
apparent survival. We compared model rankings of apparent survival and
parameter estimates based on combined genetic and video data with those
based on only genetic data. We observed 42 mother-offspring relationships.
Of these, 21 (50%) would not have been detected had we used hair DNA
alone. Moreover, video data allowed for the cub and yearling age classes
to be determined. Mean annual fecundity was 0.42 (95% CI: 0.27, 0.56).
Maternal identity influenced offspring apparent survival, where offspring
of one mother experienced significantly lower apparent survival (0.39; SE
= 0.15) than that of offspring of four other mothers (0.89-1.00; SE =
0.00–0.06). We video-documented cub abandonment by the mother whose
offspring experienced low apparent survival, indicating individual
behaviors (e.g., maternal care) may scale up to affect population-level
parameters (e.g., cub survival). Our findings provide insights into
evolutionary processes and are broadly relevant to wildlife ecology and
conservation.