Walking Buffalo, would you agree that buck antelope fawns born in wet years will have larger pedicles from the day they are born until they die? A buck born in a year with great moisture will likely still grow above par massive horns in droughty years? I would be curious what you and others think?
Colo has pretty much re-written the B&C moose record books with their introduction to Colo not too terribly long ago (in human years). The B&C magazine had an interesting article about shiras moose in Colo a while back. There has been pretty much an unlimited supply of groceries for them. There obviously was good genetics in the mix but having an incredible food source meant super fat and healthy cows/calves...and great antler growth on bulls. Many of the things Walking Buffalo mentions in his post above holds true for moose as well.
Your focus on "wet" years is likely seasonally and geographically specific. Where are you referencing and do you mean "wet" summers or winters?
I'm not aware of any research specifically analyzing Pronghorn fawn pedicle size with seasonal weather. But lets consider how would we get horn core (not pedicles) measurements from fawns.. maybe not a study anyone wants to do.
I have read some research into adult Pronghorn horn size related to seasonal weather during their gestation period. There does indeed appear to be a direct positive relation to what is suspected to be health of the dam during pregnancy and the production of larger bucks.
Just speculating, but I would expect fawns born from mothers at peak health during pregnancy are not only bigger in overall body size, but in horn core size as well, which just may be the factor that leads to larger than average horn sheath size. There is some pretty detailed research in Bighorn Sheep regarding ewe and offspring health/size and future horn sheath growth rates.... Horn sheath MASS increased along with birth weight. Now note that horn core size was not measured. Is there a correlation between horn sheath volume and vitality? Yet another mystery we can spend some time and money on....
I am from Alberta where the greatest strain on Pronghorn health is the extreme weather during winter, particularly heavy snow and a late spring. Many of our Pronghorns are migratory, so not only do they have to survive winter, the more extreme winters tend to see an increase in migration distance travelled. Kind of a double hit. For our population, a series of mild winters after a severe winter mortality event seems to lead to a year class or two of bucks with exceptional horn growth. The occurrence of "wet" summers just doesn't seen to do a lot for horn growth.
For intrest and this is just anecdotal. In Alberta we recently had a couple of hard winters in a row that hit Pronghorns really hard. A few years later and after a couple of mild winters, the bucks were still typically below average in horn size. I had been expecting to see a year class of Big horned bucks, having seen this phenomenon happen before. A few more years past and suddenly this last year the horn size exploded! BIG bucks everywhere. I wonder why there was this delay in vitality.... perhaps the does that survived the hard years were simply too old to produce exceptionally vigorous offspring? But their offspring could! The timing fits. Just a theory within the theory.
Your observations for Co moose fits right into this concept. Low density populations in great habitats with low stress (winter and predation) are a potion for producing big racks.
- Alot of "good genetics" with critters, IMO, is a result of the habitat over long periods of time.
