Pesticide and even herbicide use are more likely causing the decline.

tj

I don’t know what it is, but something is off. The Gulf Fritillary have been arriving late for the last couple of years, and they never get up to the usual numbers. This year, the Tiger Swallowtails were late, still didn’t catch up. But this might have been a late Frost after everything already leaves out. Way less hummingbirds and chimney swifts lately in my bird world. Also fewer toads, but the frogs seem to be doing fine. I haven’t seen as many rat snakes as usual, but saw 2 red bellied water snakes. A Monarch arrived 3 days ago to lay some eggs. This is really early. I usually have them in Spring, then again in mid August. There are an awful lot of wasps getting all the sulphur caterpillars. They even got most of the milkweed Tussock moth ones. On the other hand, the last generation of the Pipevine swallowtails was too successful. Now I have tons of eggs and tiny caterpillars on my barely recovering plants. And it looks like nobody nearby is growing any and would be able to adopt some caterpillars. Bees are doing alright I think. Even saw one that Seek says is a Southern Plains bumble bee. Long report on how things are on my 5 acres in SC :)

I added the purple outlines, and the last three years of data (both within outline, and in the graph).

There are so many windmills in W TX, OK, KS, it would be difficult for any migrating creatures to traverse those lands. Thousands of them in every direction, as far as the eye can see. I don't know how much of a factor they are for any particular butterfly or bird, or other animal, but it can't be possible that they aren't a factor at all for flying things. No matter how many pics I took, only the closest ones show up well but in person there are so many that it's hard for your mind to take it all in.

I think it is more than just butterflies. Population numbers of most insect species have declined, often dramatically, since the 1990's. Many species are endangered or will be endangered soon. I am 76 and remember when I was young insects in general were much more numerous.

I just saw my first Eastern Swallowtail of the season yesterday. I see quite a few if them along with black, spicebush, and zebra swallowtails, and a bunch if others, but I don’t see a lot of monarchs. They are uncommon enough that I grab my phone to take a picture when I do spot them.

The days of needing to frequently wash dead bugs off the headlights during the summer are well behind us. I count myself lucky though because we’ve only got one neighbor who has a lawn service spraying and he is 4 houses down the road!

I'm so sad for this beautiful planet. :(

I suspect the most immediate and widespread threat is all of the herbicides and pesticides being used by farming, lawn services, and some home gardeners. Genetic alterations (GMO) of some crops could be a factor.