I hunt groundhogs more than anything else to be honest, just a great way to spend a day in the spring/summer. In fact, I've shot so many over the last 8 years or so that most of my own inspiration to go now has to do with giving friends/family the opportunity. I've even threatened to not even bring a rifle of my own..just binoculars!
That said..and to put it into perspective...we're lucky to shoot 2-3 a day if this past summer is any indication. There were even a few 1 or 2 groundhog days. Best day ever (about 6 years ago) was 16 in one day between my nephew and I, and we even left some for next time.
Thinking of Hoyt's comments about not hunting them~I sort of got into AFTER their population started to decline...so my perspective was never an "I have to conserve"...it was more "this is the reality". It's only in threads like these, and in talking to old timers that I realized how big a problem they once were. They are a pain in the a** on working farms, make no mistake...so I have zero hesitation letting the air out of them. One farmer friend I know was cutting hay a couple of years ago on the side of a hill on his property, and one of the back wheels on his tractor hit a mound of rocks left by a groundhog. Nearly rolled the tractor. I actually got a call from him, some friendly ribbing that I wasn't visiting his farm nearly enough. lol
As for my opinions on their population decline~again, my perspective is what it is...but the reduced numbers I see TODAY on farms compared to when I even started would have to point towards crop rotation. I mean, their preferred type of ground consists of sand/rocks mostly, key ingredients for water drainage. If you don't have those, you probably don't have groundhogs either. Considering I've seen one farm have these ideal conditions when surrounding farms don't...I can see how it's easy to have the impression that "they're gone". Given the choice, groundhogs prefer hay fields from what I've seen, second in line would be soybeans. Grains~if planted after hay, they may still stick around...but be found on field edges mostly. It seems to be the presence of corn that ends the party. Fast. I've met plenty of dogs out where I hunt that also take exception to groundhogs and make killing them a priority. I've heard that from the farmers, and I've seen the evidence. lol Most farmers have at least a 22 that they'll take a run at them with too. I've fixed/cleaned-up/zeroed scopes on some of these old beaters.
Anyhow, unlike gophers out west (maybe my favorite thing to do, ever)...you could take 10 rounds with you groundhog hunting and likely never go through them. If we hunt long/hard, 5-6 groundhog days are very possible, and those are ones I shoot. It's rare that I don't see 2-3 others that I could easily take, but something about their location doesn't allow for a 100% safe shot. Crest of hills, farm house in the distance/same direction, people plowing a field over where the shot might startle them....that sort of thing. Common sense stuff.
It's allot of fun, but every year it seems...there is less hay=less groundhogs. Aging farmers are often keeping their land to live on, but letting other cash croppers (right term?) come in and farm their land. It's rare that the hay stays. The impression I get is that they're often only growing enough for their own needs, not to sell.