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Joined: 03/20/2012
Posts: 9
In your opinion why has the

In your opinion why has the deer population declined so much in 4 years? I know there was a bad winter a few years ago, but it seems like it is still declining after this past winter which was very mild? It also seems weird that in a select few areas like middlepark the population is just fine? What factors do you guys think are playing in to this?

exbiologist's picture
Location: Colorado
Joined: 09/19/2008
Posts: 2397
A million different things...

It's not at alal uncommon for deer to suffer from a big winter kill, but I think the main reason that they haven't recovered is due to habitat issues.  Predators can only suppress the population in the short term, the same predator numbers were present 4 years ago too, so I wouldn't be so quick to blame them.  Also, take a look at the quotas, only Middle Park managed to actually fill the lion quota this year.  I'd certainly like to see an open lion season during the rifle elk and deer seasons, and the increased bear tags may help fawn recruitment. 

More than likely the populations were higher than the habitat could support over the long term, but that's how hunters like it and so that's how things are often managed.  When major catastrophic events hit, that habitat doesn't rebound as quickly as it needs to to support theose previous populations when they've suffered more grazing and browsing pressure than they could sustain.  So, with that winter, plus a 2nd heavy winter, you're still suffering the effects of a lack of two major cohorts (age groups) of does that would be highly productive right now.

The oil and gas issues I'm sure don't help, fire suppression, lack of new deer forages (lower carrying capcity per acre and fewer acres now available, and habitat fragmentation so fewer contiguous acres of forage-therefore more pressure on those contiguous acres-see how this cycle can be tough on things?), elk outcompeting deer (look at the hedged winter ranges around the Flat Tops or Gunnison basin-the vegetation height is higher than deer can usually reach).  Unfortunately you can't blame one single thing, but that doesn't mean something can't be done.  Given that the populations were almost twice as high just six years ago, I have little doubt that we can return to those levels. 

You'd think that a droughty year like this year will be bad for recruitment, and that may be, however, I'd guess that this will be a heavy fire year, which will knock back a lot of coniferous encroachment in some areas that can use it.  So, more than likely these are short term losses, I just would have expected more gains across the board by now.

Oh and one other thing, with this low snow year, it's also possible that the surveys weren't as good as normal in the trend areas because it's harder to see the game when they aren't moving and they likely weren't as concentrated in the winter range.  I would expect really good fawn recruitment from last year with the wet summer and mild winter, but it may not show up on this year's survey.