American Painted Lady from 'TexasPuddyPrint'

Painted Lady

Red-spotted Purple

Black Swallowtail

Gray Comma

Giant Swallowtail

Orange-banded Butterfly (Southern Texas Only) from 'TexasPuddyPrint'

Blue Metalmark (Southern Texas Only) from 'TexasPuddyPrint'

So... What's Going On?

I certainly don't have any answers for you in this article (I wish I did), but I can share with you what I learned while looking for an explanation to the low numbers early in the season.

Weather Conditions — A July 18th blog from the University of Kansas's Monarch Watch offers several answers to the questions regarding Monarch counts. The over wintering Monarch population in Mexico was slightly down and mortality rates were about normal across all regions. The spring migration into Texas was late but reproduction conditions were favorable. In May and June however, temperatures were cold and rains were plenty. Such conditions says monarchwatch.org, likely reduced the population. I can only imagine the same was true for other species.

Habitat Destruction — Many on the forum cite habitat destruction as the main cause of a general decline in butterfly populations. Large-scale conversion of woods, wetlands and meadows into developments endanger butterflies, songbirds and native host plants alike. As grasslands go by the wayside so do many native plant species that are so important for larval butterflies.

Habitat Familiarity — Some however theorize that their gardens are not well established on the butterfly rounds. I've heard this theory before regarding hummingbirds and attribute it to my own garden's inability to attract summer hummingbirds.

Butterfly Counts and Other Data

Each July the North American Butterfly Association (NABA) enlists Citizen Scientists to participate in a one-day Butterfly Count. With much research, the data may be interpreted in a number of ways. Some simple Internet browsing shows interesting results.

Take this year's count in Mercer County, New Jersey for instance. Observers in this area recorded record highs in some species, and their overall count for 2008 is higher than it has been in five years. The Louden Wildlife Conservancy in Virginia posts similar results, citing the spring rains for increasing nectar and host plants. This data illustrates a two-year upward trend for observers in that area. In addition, the Louden count saw their "highest number of different species: 55 in total and some of these were quite rare." The news is not always good — counts like this also confirm a continued decline in some species like the Red-Spotted Purple. The good news continues north to Canada where the Ojibway Nature Center in Windsor, Ontario. "New high counts were set for Spicebush Swallowtail, American Copper and Hickory Hairstreak." With just minimal research, it appears that the numbers in the east were good this year.

There were some typical results in the Midwest like that reported from Purdue University in Indiana, as well as in South Texas where numbers were about the same from last year, but fewer species this year. Out west the Oregon NABA chapter 2008 Count results appear less encouraging. Numbers in two locations are roughly half of what they were five years ago (2008=696; 2003=1811). To participate in a butterfly count in your area, visit NABA for local chapter information.

What You Can Do

As one forum post mentioned, "...I don't think GARDENERS can make much of a difference." In the larger scope of things that's probably true. Unless you are an urban developer who can incorporate some changes into routine planning, you probably don't have control over large-scale habitat destruction.

But if you want to increase the local population, you might certainly make a difference. Let's talk Host Plants. Without a doubt, the best thing you can do is to plant or protect host plants for butterflies. Not every butterfly has a host plant that you can conveniently find at your local nursery though. If you are concerned about populations, find out what butterfly is in your area and then familiarize yourself with the plants on which it feeds. For example, if you are going to remove a few trees or bushes on your property for reasons other than the health of the tree, take a moment to see if they are a host plant for a species in your area (at the end of this article, you'll find a list of some common butterflies and their larval host plants).

Today I'm happy to say that the butterfly numbers in my garden are rising as were those of some of the eastern butterfly counts. Although the data does not point to any concrete answers, several factors are certain. Habitat destruction continues across North America, contributing to the demise of several host species. Rainy weather contributes both positively and negatively on populations. While spring rains slowed early generations, they also improved host plant growth, allowing for more prolific reproduction. It will be interesting to see what the October Texas populations show.

If you are planning a butterfly garden, discover what butterflies are in your area and add corresponding host plants. Don't forget the nectar plants. Choose plant varieties allowing staggered bloom times and nectar will always be available for your butterfly friends. Consider getting involved in local butterfly counts to increase your life list. Most of all have fun and enjoy the show.

Gulf Fritillary
from 'Xenomorf'

Zebra Longwing
from 'Xenomorf'

Cloudless Sulphur
from 'mellielong'

Zebra Swallowtail
from 'Magpye'

Zebra Swallowtail
from 'mellielong'

Mourning Cloak
from 'Sarahskeeper'

Thanks to Dave's Garden members who contribute to BugFiles. Images with no credit are author photographs.