Thanks to Lois Braun for the nudge that we'd neglected to post our observations on hazel ripening this year. Sorry about that; I'd actually thought we had.
Yes- the hazels are ripening well ahead of "normal" this year, due to the extreme heat, and likely also due to drought. The drought here at Badgersett has been sufficiently severe that we have immediate neighbors whose corn is looking like a dead loss; maybe salvageable as silage, but no grain; but the hazels, chestnuts, and hickory/pecans are just unaffected (vegetatively) by it.
The hazels ARE getting ripe early, though; and some of them are ripening this year before the nuts turn fully brown. I've seen that happen both in hazels and chestnuts, in years with varying kinds of stress; "color" is not as important as other factors, apparently; and nuts may be fully ripe and separated from the tree long before they turn the colors you expect.
The critters, however, know perfectly well when they are ready, and don't wait for the color. Be aware; and beware- the drought and heat may INCREASE the critter pressure on your nut crops. When other food sources fail, they will come where the food is.
When watching out for animal thieves, also keep in mind- their behaviors will change, from year to year. Old crows teach young ones- this is now accepted by the fussiest scientists; and they learn how to avoid YOU. Crows learn when you are likely to be in the field; and will time their visits so you'll never see them. They carry clusters away; so you won't see nut shells or husks; the clusters will just gradually vanish from the field. Our crows are in the hazels field at dawn- until we convince them we're there too; waiting for them. They are also smart enough that they will stay away, if they know you're waiting with the shotgun. But you have to prove it.
Our biggest pest problem right now is red squirrels (Tamiasciurus hudsonicus). When I moved here in the '70s, no one had ever seen one here. But; maybe it's climate change? - they have invaded, and are now established; and are much faster and more evasive than gray or fox squirrels. Harder not only for us to catch; but harder for the hawks, too. They're getting more hazels than I like right now; and they don't wait for full ripeness before starting to steal.
Other pests will also vary from year to year; bluejays, deer mice, and "striped gophers" - will do varying amounts of thieving; changing with the year, the acorn crop, and the size of your planting.
So- NOW is the time to be checking your crops! Don't take it for granted that just because there was a heavy crop on last week- it will still be there next week.