Juliet - February 1, 2014January, the birth month, is over, so the cubs we look forward to seeing and photographing with Black Bear Field Course participants this summer should already be born.
Our best guess for clan members giving birth this year is 24. That includes: 8 mothers we see regularly (Shadow, Lily, Braveheart, Donna, Ursula, Shannon, Bow, and Star), 7 likely first-time mothers we see regularly (Fern, Aster, Daisy, Sophie, Sybil, Jani, and Oliana), and 9 females we seldom see (Faith, Nita, Shauney, Rose, Willow, Wendie, Vanna, Buffy, and Cora).
They should have about 52 cubs, bringing Shadow’s clan to about 249. A goal this summer, including during the courses, will be to document the sexes of the cubs, obtain photos for the identification scrapbook, and add 2015 to the reproduction record we began in 1995. That record has gone far beyond what we ever would have anticipated. We know of no other clan record like it.
Juliet and cub - February 1, 2014One of the pieces of data we obtained was how litter size differs between non-fed bears in our old study area (1970-1980) and fed bears in this study area (1995-present. We thought litter sizes might be larger with more food, but they were about the same. Center to center, the old study area is only 30 miles ESE of this study area and is in similar habitat. The main difference is that bears in the old study area were without the supplemental food bears receive in the present study area, which is one of the reasons we studied bears here. For litter sizes in the old study area, I referred to Table 10 on page 53 of Effects of food supply and kinship on social behavior, movements, and population dynamics of black bears in northeastern Minnesota and used data only from the “Natural” part of that table.
Comparing data sets, the average size of 17 first litters in the old study area was 2.12, and the average size of 23 first litters in Shadow’s Clan is 1.91 (10% lower).
Subsequent litters were higher in both studies. The average size of 35 subsequent litters in the old study area was 2.51, and the average size of 57 subsequent litters in Shadow’s Clan is 2.67 (6% higher).
Juliet licking snow - February 1, 2014Overall, the average size of all 52 litters (first and subsequent litters combined) in the old study area was 2.38 cubs, and the average size of all 80 litters in Shadow’s Clan is 2.45 cubs (3% higher).
We have yet to run statistical tests to see if the 3% is statistically significant. If anyone wants to run that test, litter sizes in the old study were 4 litters of 1 cub, 24 litters of 2 cubs, and 24 litters of 3 cubs. Litter sizes in Shadow’s Clan were 6 litters of 1 cub, 33 litters of 2 cubs, 40 litters of 3 cubs, and 1 litter of 4 cubs.
In today's 11+ minute highlight video there was a fair amount of activity in Juliet's den with her crawling toward the den entrance to lick snow, chewing a bit more on the overhead log and offering some nice views of the cubs. It was a bit warmer than the previous day with a high of 11°F and low of -7°F.
YouTube: https://www.youtube.com/watch?v=3fffULVh6aU
Vimeo: https://vimeo.com/118417389
Archives: http://www.bearstudy.org/website/research/2014-juliet-archives.html
At the Bear Center, the word is that Maureen will finish the mural this evening, and the habitat creators will resume work in the morning as we watch at http://www.bear.org/website/live-cameras/live-cameras/nabc-webcam.html.
Thank you for all you do.
Lynn Rogers, Biologist, Wildlife Research Institute and North American Bear Center