The goal of this project was to determine to what extent grizzly bear predation might be influencing caribou populations in west-central Alberta using existing datasets supplemented with additional key data not currently available.
Project Objectives:
- Predator prey habitat models – With currently available data sets from GPS collared grizzly bears and caribou, determine the spatial and temporal habitat use and movement patterns of these species surrounding anthropogenic features relative to other habitat characteristics within mountain caribou ranges of the A La Peche and Redrock-Prairie Creek herds.
- Kill site/feeding investigations – Undertake the collection of new and important field data to determine the kill rates of caribou) by grizzly bears in relation to gender and age class and landscape characteristics associated with anthropogenic features and the current habitat matrix.
- Isotopes – Using captive grizzly bears develop and validate new techniques to quantify caribou within the diet of grizzly bears from scat and hair using stable isotope techniques.
This is Year 2 of a two year project. Objectives 1) and 3) were completed in Year 1 and reported in the Year 1 Final Report.
Objective 2 Activities to Date:
fRI staff collared 2 grizzly bears this spring within the caribou ranges in west-central Alberta to make a total of 11 grizzly bears providing location data in which location clusters were extracted. As many as possible were visited to determine whether a carcass was present at the cluster. They used a similar method as in 2014 to extract and select clusters from the data and is outlined below
GPS data Cluster Creation and Selection – Grizzly bear GPS collar data were downloaded from the Followit ©website. Data were cleaned and run through a python script that identified groups of sequential collar locations within 50m of each other. These groups of collar locations were defined as a cluster. Clusters > 10 hrs in duration were visited as well as a random sample of clusters <= 10 hrs. In addition, a manual inspection of each grizzly bear’s movements in a GIS was conducted and additional clusters of interest were added to the list to be visited. Clusters of interest included those where the bear suddenly changed direction and ended in a cluster or if the bear revisited a cluster.
•Site Visits – The python script used to identify clusters also determined the centre coordinates for each cluster. Access to each cluster was conducted via a helicopter, truck, ATV and then on foot. Often a bear bed or carcass site was within 10m of the center point. A 30-50m radius search from the cluster centre was conducted. Other bear sign included digging for hedysarum or ground squirrels, anting, or heracleum, berry or other herbaceous feeding. Any scat found at the cluster was examined for bones or hair and if found, we would visit the previous cluster in an attempt to locate a carcass. Also any scat with hair were collected for later identification of the hair under the microscope.
•Recorded Data- At each cluster, photos were taken in each cardinal direction as well as photos of any observed bear sign. At carcass sites, we took detailed photos of any remains and collected bones or hair that could be useful for species identification and/or ageing. We recorded and took pictures of any observed sign of predators in the area.
•Results to Date: In 2015, we visited 230 clusters from 11 bears – 6 adult males and 5 adult females. We found 35 ungulate carcass sites. Of the 35 ungulate carcasses, none were confirmed caribou; one was a deer, 22 were moose calves, 7 were adult moose, and 1 was a yearling moose. In addition hair extracted from scats found at 12 clusters not associated with a carcass and 1 cluster with a calf of unknown species will be examined under the microscope to determine species. The earliest clusters to be visited occurred in mid May with the first moose calf kill occurring 22 May 2015. Similar to last year, we were restricted from flying into the mountains after the 22 August due to concerns expressed by ESRD of disturbing hunters, which resulted in cluster visits ending in August for mountain bears. However, two male bears in the foothills continue to send data so we plan to continue visiting cluster into October. Data analysis with the final data set will begin in early November once cluster visits have ended.
