Greater Washtenaw County Butterfly Survey Homepage

Greater Washtenaw County Butterfly Survey is an ongoing study of butterfly populations and important habitats in southeast Michigan. It was started by John Swales in 1994 at the suggestion of the late professor and lepidopterist Warren H. Wagner of the University of Michigan. Special emphasis is placed on finding and monitoring of populations of butterflies at risk as designated by the Michigan Department of Natural Resources and Michigan Natural Features Inventory. Secondary emphases are placed of finding southern immigrant butterflies and early and late species sightings which may be indicators of global warming.

The area covered in the study includes all of Washtenaw county and parts of Wayne, Monroe, and Lenawee counties. Some of the principal butterfly sites in this region are Crosswinds Marsh in Western Wayne county, Petersburg State Game Area in southwest Monroe county, Embury Swamp in northwest Washtenaw county, Sharon Valley and the Noggles Road area in southwest Washtenaw county.

Each year coverage and butterflying expertise has improved greatly as indicated by the growth of yearly species totals and known breeding locations. This year a greater effort will be made to document the habitats and hostplants used by the rare and uncommon species of the area.

Most butterfly records are sight records only. Binoculars and butterfly nets are carried into the field as aids to identifications. A few butterflies are vouchered to either seek expert opinion on questionable ids or to document a rare find for Michigan Lepidoptera Survey and Michigan Department of Natural Resources.

Main Observers:   Barb Barton, Martin Bialecki, John Farmer, Roger Kuhlman, Chris Rickards, John Swales, Roger Wykes

Butterfly News--The First Butterflies of the 2009 Season

Record 68 degree sunny weather on Friday March 6 produced the first butterflies of the season in southeast Michigan. I found two Eastern Commas (Polygonia comma) in Tuebingen Woods in northeast Ann Arbor near the Traverwood branch of the Ann Arbor Library around 3 pm in the afternoon. The first Comma I saw was pretty sluggish and it would generally only fly a few feet before landing on the forest floor and orienting itself to best catch the rays of the sun. However the second Comma seen vigourously zipped by me in extended flight.

Yesterday's sighting of the Eastern Commas is the second earliest season record for this species in the 15 year history of the Greater Washtenaw County Butterfly Survey. An Eastern Comma was only seen earlier in the season in the year 2000 when the first one was found on March 4. By contrast last year the first Eastern Comma was reported on April 3!

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Monday afternoon (March 16) I walked the trails at Matthaei Botanical Gardens in Ann Arbor and found four Mourning Cloaks (Nymphalis antiiopa) and one Eastern Comma (Polygonia comma). I got a report from Martin Bialecki that he found a Milbert's Tortoise Shell (Nymphalis milberti) on Sunday in southwest Washtenaw County.

With sunny conditions and warm temperatures, conditions should be good to see more over-wintering adult butterflies today in sheltered locations in southeast Michigan counties.

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Wednesday afternoon April 1 while working on my backyard garden, I saw a Cabbage White (Pieris rapae) come fluttering by. It was my first butterfly of the season that emerged from the pupal stage and its chrysalis. The Mourning Cloaks, Eastern Commas and Milbert's Tortoise shells reported earlier in March were overwintering as adult butterflies.

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Thursday afternoon along Flemming Creek at the Matthei Botanical Gardens in Ann Arbor I saw my first Spring Azure (Celastrina ladon) butterfly. This butterfly species is the second one that has emerged this season from a chrysalis in the pupal stage in the southeast Michigan area--the first being Cabbage White (Pieris rapae).

In terms of the past 12 years of butterfly surveying of the Greater Washtenaw County area, this year's April 9 sighting was only slightly earlier than normal. Both the mean and median historical first sighting date for Spring Azure are April 11. The earliest date one was ever seen was April 1 in 2000. The latest first sighting date was April 19 in both 2003 and 2004. Last year the first Spring Azure was found on April 17.

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On Friday April 17 I went looking for Brown Eflins (Incisalia augustinus) near the Discovery Center (formerly the Geology Center) in Waterloo recreation Area in northwestern Washtenaw County. Conditions were excellent for their emergence but unfortunately I found none--probably I was there a few days too early. However the first Mustard Whites (Pieris napi) of the season were flying. I netted a couple of Mustard Whites and tried to take pictures of them. Image quality of the butterflies in the net are a bit poor but you can see the distinctive features of the species the green-gray edging along the veins of the underside hindwing and the yellowish orange spot at the base of the hindwing. Mustard Whites are an uncommon butterfly in our southeast Michigan area and the Discovery Center area of wet woodlands is one of the best places to find this species.

NABA and Other One Day Butterfly Counts in the Survey Area.

Sightings Data of the Greater Washtenaw County Survey

Butterfly Season Reports

Butterfly Resources--General

Website maintained by Roger Kuhlman