Gonzaga, not to be mean but how do the alpha's teach those youngsters how to take down spring calves?The females aren;t dropping them until April/May and by the time those youngsters are big enough to go on hunting trips those once little calves are off limits to coyotes due to size and being very ornery come august. If your friends calve in Feb?march as the norm and no pup's yet present, how big are those calves come time for the youngsters to be taught?
Also coyotes are not much in the way of paunch eaters, in fact most will lay out the paunch to the side and leave it for the birds. The majority of coyotes will eat heart and livers but then onto meat. I have seen my share of calf kills which are far less than lamb kills, you see lambing in May makes them an easy learning tool come august and Sept when those pup's are big enough to take in the foray, those spring calves will be well over 200+ pounds by that time. Much easier pick ens in August and Sept than spry calves.
Most of the kid antelope that get killed are at birth to weeks old, and yes the coyotes do target them and do take there share, of course the more coyotes and more antelope the better the odds and numbers taken. You will get less vocal response during that time of year for sure for a window of time. If your getting adult antelope killed in numbers by coyotes I'm betting your study took place during harsh weather conditions. You get deep snows and antelope have a hard time of it and add in coyotes needing meals and yes the opportunity for larger kills can take place is it the norm? Not with adults goats, as they can out run them with ease 60 mph and will lay out on open flats with far ranging as there protector when the weather is good.Weather conditions change the dynamics from the norm. In areas of Wyoming the antelope take a hit from the coyotes, but that is on kid's and not a large killing of adults, weather,cover all play into it as well as coyote density's and antelope numbers. They are not "packing" up in May/July killing these as packs, but numbers of pairs that are defending territories and food rights for the youngsters.
As far as size yes a 250+lb calf can kick the crap out of you or I and not many coyotes are willing to chance that when easier meals and weather dictate a better outcome feeding on something else. Again I don't watch the video how big of calves are we talking that are 100% confirmed coyote kills?
Fall calving while tougher for the cows and calves as many don't put on the weight their spring brothers do are more susceptible to coyote depredation because you have a larger population of coyotes in the fall than you do the spring, times are tougher for all involved and you can increase your depredation, I know less and less that winter range fall calves and those that do keep them in close and a "pack" would have to be either really bold or stupid to get involved with 100+ fall calf/cow pairs in more confined pastures.
% of loss means something for sure and knowing how to confirm loss as well. Not every critter fed upon by coyotes are killed by coyotes. Sure they do their part No doubt, but some story's just don't add up.