I saw this article in the Bergen New Jersey paper which I thought might be of interest to DGer Butterfliers: http://www.northjersey.com/recreation/news/Chill_rain_factors_in_butterfly_decline.html
Chill, rain factors in butterfly decline
Monday, July 27, 2009
BY JAMES M. O'NEILL
The Record
STAFF WRITER
A wretchedly wet June has wreaked havoc on the summer's butterfly population, causing a steep decline throughout much of New Jersey, according to experts who oversee butterfly counts.
Normally, about 400 pearl crescent butterflies are spotted in a Sussex County count. This year: 83. They say a range of factors could have contributed to the decline, from deer eating the favorite plants of butterflies to a lack of snow cover last winter, leaving butterfly caterpillars prone to desiccation and exposed to predators. The principal culprit, however, was the chilly, cloudy June weather that destroyed eggs, caterpillars and chrysalides and delayed the blooming of wildflowers that provide nectar for adult butterflies.
"The numbers are down very dramatically," said Jeffrey Glassberg, president of the Morristown-based North American Butterfly Association, which sponsors hundreds of counts across the country.
"Butterflies are important because they are the prime pollinators of some plants," Glassberg said. Caterpillars are also a significant food for some birds.
While butterfly counts can spike and dip, this year's decline seems more widespread, experts said. The largest count in North Jersey, the Springdale count, covers southern Sussex County. It averages about 4,000 sightings, but this year there were 2,515, said Joe Burgiel, president of the North Jersey Butterfly Club.
"There certainly were some real horror stories," he said.
For instance, the count averages more than 200 banded hairstreaks, a gray-winged butterfly with flecks of black, white and orange. This year, there were seven.
Another bust was the pearl crescent, which has an ornate yellow and brown pattern on its wings. Normally about 400 are counted, and last year there were 616. Only 83 were spotted this year.
Nancy Slowik, naturalist at Greenbrook Sanctuary in Tenafly, said this year's count logged only seven species, compared with 12 last year and 15 in 2007.
"Butterflies are good barometers of the environment because they're very sensitive to changes," Slowik said. "There's never just one reason for butterflies to decline, but this year weather was one of them. Whenever there's a cool, wet spring, caterpillars are very susceptible to fungus."
Only 69 individual butterflies turned up in a count on Garret Mountain and in Rifle Camp Park in Woodland Park this month, compared with 82 last year, said Pete Both, a count volunteer.
"So much depends on the weather, but we're also losing a number of the butterflies' host plants, especially around Barber's Pond, where people tramp through and where deer are a factor," he said.
Butterflies have a complicated life cycle and, depending on the species, can winter in the egg, caterpillar or chrysalis stage. The spring weather could have affected butterflies at any stage of their life cycle, Burgiel said.
Adult butterflies live for only a few weeks, so they can be affected if their preferred plants bloom late, Glassberg said. Because of the cool, cloudy June and mild July, flowering plants that butterflies prefer for nectar, such as buttonbush, were delayed in blooming.
Many other factors can contribute to low butterfly populations, experts said. Experts worry about a parasitic wasp that lays eggs on butterfly caterpillars. The wasp larvae burrow into the caterpillar and consume it, said Michael Gochfeld, co-author of a book about New Jersey butterflies.
Hungry deer, meanwhile, can consume plants that are caterpillar food or that the adult butterflies use for nectar, Slowik said. Widespread use of herbicides could also harm butterfly populations.
"People try to get rid of weeds by spraying, but what we consider weeds may be important to butterflies," Slowik said. Those plants include mountain mint, native goldenrods, wood and false nettles, swamp milkweed, timothy and blue grass, and many clovers.
At the Wallkill River National Wildlife Refuge in northern Sussex County, the overall population reached a seven-year low this season. Red admirals, which had a boom year in 2007 with 223, were down to only one this summer, said count leader Ken Witkowski.
Fred Weber, a volunteer at the Celery Farm in Allendale, also noted a precipitous decline in red admirals, black butterflies with distinctive red bands.
"There were millions of red admirals a few years ago, the next year they were way down and this year they're practically non-existent," he said.
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NABA July 2009 Butterfly Count Results
Judy,
Very interesting,, I haven't seen my Red Admirals yet this year and I have lots of weeds. They love the cudweed down here. My Red Ring Milkweed is growing and hopefully we will get some rain soon...
Elaine
So sad, I think the butterfly populations are down everywhere, they certainly have been here.
Josephine.
I think that's why it's so important that we boost the numbers through our efforts to raise them. I think nature is all about balance and so for everyone who is out there spraying pesticide or eliminating native plants, I like to think there is a dedicated gardener out there doing exactly the opposite.
In good news, this has been a great year for me so far. I'm raising species that I never had in the last two years - Sleepy Orange and now Tiger Swallowtails! Let's hope this is just a normal downturn in the population. Maybe the butterflies are indicators of the economy, LOL!
Melanie
question from a casual observer: I understand that raising butterflies will increase population by the mere fact these are ones protected from wasps, deer, chemicals, etc. But does raising butterflies attract more non-sheltered butterflies to one's garden? Stated otherwise, do more butterflies come into your garden when the see butterflies already hovering there?
I hope that makes sense. I have focused on planting host & food plants but the impatient side of me doesn't see enough butterflies for my efforts (more, yes, but not the swarms I envisioned in my mind, lol).
T, think I can take up another gardening interest? he he he. Good article. In my area we are in the opposite side of the spectrum with record breaking drought. Butterfly population should be down here as well, right?
Butterflies tend to chase each other off so I'm not sure that seeing other butterflies is an attractant. What really keeps them around is having host plants. Lots of people will plant nectar plants and the butterflies will come visit, but if you plant their host plants they'll move in and stay. I think each year I've gardened the population goes up a bit, but sometimes you'll just have a bad year or conditions will be a little off. For example, the year 2004 we had four hurricanes hit Florida and the butterflies had a bit of a rough time.
Melanie
thanks for the explanation. I will continue to plant host/nectar plants.
Nery, I don't know if seeing butterflies will bring more, but it does signify that there is something about your place they like and they will probably stay in the habitat. Of course, concentrating on planting host plants here and there is always helpful and a fun gardening 'challenge' to try to get more species. You don't have enough going on in your garden, anyway, and you need more to do! (-:
I read somewhere that a county around here was encouraging every single homeowner to plant one dogwood for the wildlife (instead of Bradford pears, for instance). Apparently, around here a wide range of species derive some benefit from dogwoods (not just butterflies nectaring and using it as a host plant). Anyway, that is just one example of citizen activism.
I saw another community appeal for everyone to plant several milkweeds for the monarchs and other butterflies. Besides making these straightforward appeals that are 'media friendly' I think such p.r. raise awareness of simple ways people can 'go green' and gets them involved and aware and to join the 'experience'.
Any way, it's fun to plant for the butterflies, and I find some bit of solace in knowing the 'pros' have announced the numbers are down, and it's not just our garden! And next year will surely be better.
If you are interested in the drought and rain conditions throughout the U.S. here's an interesting set of maps, the Palmer Precipitation Index, to peruse: http://www.ncdc.noaa.gov/oa/climate/research/2009/jun/drought-indicators.html
Bad year for me here except maybe for Monarchs and Cabbage whites. I thought for a while that the monarchs were chasing of the others, but I've gone to 3 of my regular locations for BF spotting and it's been down as well. What really concerns me is the lack of silver-spotted skippers. TONS of them last year.
I see now that Minnesota is recording a 38% drop in Monarchs this year.
http://minnesota.publicradio.org/display/web/2009/08/19/minnesota-monarch-butterfly-population-falls/
Well, I'd never seen a Silver Spotted Skipper in my yard until this year so maybe they're just moving south. Oddly enough, there was an article in the paper about how the bald eagles have arrived early this year, as nesting season does not begin until Oct 1st and they're already here. Although, it did mention that they are not showing nesting behavior yet. Then, my dad was delivering mail and saw a bunch of Blue-Wing Teal flying overhead and he says they don't usually come for a few more weeks. Maybe there's some kind of weather thing going on?
Melanie
http://www.sj-r.com/homepage/x1885888388/Weather-not-so-kind-to-butterflies
Here's one closer to home for me. Seems our weather was a factor.
And I have to say that my first week of fall hummingbird migration has been slow too.
Butterfly numbers and variety are way down here, too. There used to be dozens of Cabbage Whites and Silver Spotted Skippers all summer, and I've only seen one of each, and not until the past week. I haven't seen any Painted Ladies or Frits, and we used to have those too. I guess the wet weather has put a damper on the butterfly population.
Debra