Monday, April 30, 2012

Moth program results

Our moth program with field guide author Seabrooke Leckie was a great success! We were a bit worried about the cool weather, but Seabrooke explained that many moth species overwinter as adults (rather than eggs, caterpillars, or pupae/cocoons). These cold-hardy species will fly in temperatures cooler than we were experiencing (in the mid-50s).

Seabrooke arrived in late afternoon, and we set up several sheets with different types of light (black light, mercury vapor). Moths are attracted to the lights and land on the sheets.

One of the sheet/light set ups.

We also soaked some rope in a mixture of red wine and brown sugar, and hung them out to attract species that feed on nectar and sap (many adult moths, however, do not eat at all). This mix should really be allowed to ferment, so we didn't have luck with that.

Stinky, sticky wine rope hanging from wood shed.
Seabrooke started out with a short presentation focusing on moths in the environment.

Then our group of about 30 people made the rounds of the sheets and collected moths in clear pill bottles. These were brought back into the building where Seabrooke identified them.

Seabrooke also helped my husband Darrin identify some photographs he had taken the last few years.

Our friend Don Sherwood has been raising silkworm moths. He brought along this Luna Moth to show everybody. I think this is probably one of the most beautiful moths in the world!

Here is our list of moths that came to the lights, with links to the species or genus at BugGuide, a great online resource for insect identification. Some very tiny moths ("micromoths") were only identified to genus.
The Curve-toothed Geometer. We released
all the moths at the end of the night.
  1. Unicorn Prominent (Schizura unicornus)
  2. The Gem (Orthonama obstiptata)
  3. Celery Leaftier (Udea rubigalis)
  4. Palmerworm Moth (Dichomeris ligulella)
  5. Featherduster Agonopterix (Agonopterix pulvipennella)
  6. Confused Woodgrain (Morrisonia confusa)
  7. Acleris sp.
  8. Common Acleris (Acleris subnivana)
  9. The White-Speck/Armyworm (Mythimna unipuncta)
  10. Dusky Groundling (Condica vecors)
  11. Olive-and-black Carpet (Acasis viridata)
  12. Epinotia sp.
  13. Eupithica sp.
  14. Bent-line Carpet (Costaconvexa centrostrigaria)
  15. Curve-toothed Geometer (Eutrapela clemataria)
  16. Red-banded Leafroller (Argyrotaenia velutinana)
  17. Gray-banded Leafroller (Argyrotaenia mariana)
There were also a couple of "get-aways" and some that flew near the sheets that we didn't catch.

Thank you Seabrooke for an excellent evening!

Julie Craves and Seabrooke Leckie.

Thursday, April 26, 2012

Update on European Goldfinches

Update: This paper has been published! It's open access so you can read online or download the PDF; click on title below -

Craves, J.A., and N.M. Anich. 2023. ­­­Status and distribution of an introduced population of European Goldfinches (Carduelis carduelis) in the western Great Lakes region of North America. Neobiota 81:129-155. doi: 10.3897/neobiota.81.97736


People continue to leave me comments on my previous posts about European Goldfinches in the U.S. (see list of posts below). I am still keeping track, especially of breeding records. In addition to accumulating reports from proactive observers, I also periodically look through birding listservs and eBird records. Unfortunately, any Illinois records put in eBird are filtered out of public view, but the state reviewer is working on changing this. Even so, I still have over 50 records of well over 100 birds from the past few years just in southern Wisconsin and northern Illinois alone.

Here's a map from a previous post, showing the Wisconsin and Illinois counties highlighted in red where the bulk of reports of European Goldfinch come from.

In a previous post, I documented nesting in Waukegan, Illinois, which is in Lake County. Later, I found a report online of a family of European Goldfinches at Waukegan Beach on 13 August 2009, consisting of five birds: two adults, and two juveniles, with the fifth bird likely also a juvenile. The observer posted this photo on Flickr. The day before the photo was taken, another observer saw a minimum of 13 European Goldfinches foraging in a weedy area in what appeared to be two to four family groups in an area just adjacent to Waukegan Beach.

In 2011, European Goldfinches were reported nest-building at Waukegan Beach. A report in April 2012, just a couple weeks ago, also mentioned them gathering nest material. So it seems a breeding population is well-established in the Waukegan area.

These may not be the first European Goldfinches to have nested in Illinois, as there was also a report of birds nest building at Montrose Point in Chicago, Cook County as early as 2003.

In Wisconsin, the breeding population seems centered in the Racine area of Racine County. That is around 25 miles north of Waukegan. My previous post documented a juvenile in 2009 in the Racine suburb of Mt. Pleasant. Subsequently, I received a report in late July 2009: the Scheefs in suburban Racine reported on a juvenile showing up at their feeders shown in this post.

I also heard from Sarah Anspaugh of Racine, who took the photo below of a European Goldfinch family. A pair showed up at her feeder on 13 May 2009, appeared periodically through June, and on 8 July 8 there were 2 juveniles with them.

Jane Scheef of Racine contacted me again in 2010. The pair in her neighborhood arrived at her feeder on 29 June with 5 young in tow, shown in the photo below.

I think that an eBird report of six to eight coming to a feeder in Racine in late winter 2011 may be the same residence. The largest flock I have heard about was that of 30 on 4 December 2011, also in Racine (I think this checklist is the exact location).

Finally, in between Waukegan, IL and Racine, WI is Kenosha, WI, where a correspondent named Donna has had at least one pair of European Goldfinches at her feeders. In June 2011, she photographed them with three young. She recently wrote me that a pair is currently coming to her feeders.

Unlike American Goldfinches, European Goldfinches typically nest in May and June, so be on the lookout and keep sending those reports.

Here are my other posts:

Monday, April 2, 2012

Moth program with field guide author Seabrooke Leckie

It's with great anticipation that I announce an upcoming program, a joint effort between RRBO and the University of Michigan-Dearborn Environmental Interpretive Center. Seabrooke Leckie, co-author of the new Peterson Field Guide to Moths of Northeastern North America will be visiting on Sunday, April 29, 2012. She will be giving an informal program on moths, and will be setting up her nocturnal moth-attracting gear in the campus natural area to see what is around. Late April can be fairly early for a wide variety of moths at this latitude, but with the exceptionally warm spring, it's hard to know what to expect! Let's hope the weather doesn't turn too fickle.

I can't wait to see the new field guide. It will be released shortly before the program, and Seabrooke will be happy to sign your copy (she will have some available for purchase, or you can pre-order at Amazon). This book is sorely needed, and you can read more about the story behind it, what it will include, and see some sample plates at Seabrooke's web site.

Plus, I'm really looking forward to finally meeting Seabrooke in person. I first became aware of her through her former work as a bird bander at Tommy Thompson Park Bird Research Station in Toronto. They banded a Ruby-crowned Kinglet in 2003 that I recaptured here on campus in 2005. Since then, she and I have kept in touch through our blogs and social networking. Seven years is like forever in the ephemeral world of the Internet, so it feels like we have been friends a long time. I'm eager to met her ITRW ("in the real world"), as the kids say these days.

The program will take place from 8 PM until midnight at the campus EIC. A map and directions are on this page.

The program is free, and children must be at least 12 years of age to attend. We ask that you please RSVP by dropping us a note; you can do so by filling out the contact form on the RRBO web site.

Friday, March 23, 2012

What does summer in winter mean for birds?

We are in the midst of an unprecedented March heat wave. Here in southeast Michigan, we have experienced a week of temperatures over 70F (and a few over 80F), but this warmth is not a local phenomena. Records are being shattered all over the eastern U.S. and Canada.

The growing season in Michigan is about five weeks ahead of schedule. Many insects are also making very early appearances. That, in a nutshell, is the problem with a stretch of warm weather that comes ahead of the arrival of many migratory birds.

In my previous post, I discussed the migration timing of Neotropical (long-distance) migrants -- those species that winter in the tropics.  As I mentioned there, the annual cycle of migratory birds has been choreographed by evolution to provide maximum resources at all the proper times of year. Birds wintering in the tropics take advantage of the resources available there, and fatten up towards the end of our winter. This enables them to make the journey north, back to their breeding areas in North America. As they move north, they take advantage of the insects that are emerging to feed on the new flush of leaves or opening blossoms on trees and other vegetation. A few short weeks later, they rely on soft-bodied insects such as caterpillars to feed their young. In autumn, the bounty of fruit, seeds, and nuts enables southbound migrants -- many species switch from a diet of insects to a diet dominated by fruit -- to gain and maintain the fat they need to make the long journey back to the tropics for the winter.

Favorable weather patterns can facilitate migratory flights, provided birds are on the move. Since the migratory movements of birds are primarily triggered by photo-period (day length), many long-distance migrants have not yet departed the tropics.

These birds are now already very out-of-sync with the insect resources that they need on their return trip to their nesting grounds. The longer it stays warm, the farther out of sync bugs and birds will be. This mismatch will extend into the nesting season, and could have significant impacts on successful reproduction.

However, it's nearly inevitable that we will see a return to cold weather. As reported by the National Weather Service, the average date of last freeze in southeast Michigan is not until late April.  And based on past years, most of southeast Michigan will have a hard freeze (28 degrees or lower) sometime during April.

Under this scenario, insects will become inactive, and many will simply die. They may perish before they have an opportunity to reproduce, or their eggs or early life stages will not be able to survive. If cold weather persists, it could also kill tender leaves, cause flowers to drop, or kill their pollinators. Migrants arriving during this period, or trying to reproduce afterwards, may experience a severe food shortage. Short-distance migrants such as robins, which have already started nest building, are likely to lose their first brood. These species typically have two or more broods in a season, and so may be able to raise some young later. But long-distance migrants are usually single-brooded, and have only one chance to nest successfully. If they are in poor condition they may not even attempt to nest.

A cold snap could also prevent plants from setting fruit (whether seeds, berries, or nuts). As noted above, these are essential crops for fall migrants, and a lack of resources on fall migration could cause outright mortality or late arrival on the wintering grounds, and consequently lower quality winter territories. In turn, reduced health in winter has carry-over effects that reach into subsequent seasons.

The birds most at risk are the long-distance migrants, particularly forest species. The Boreal Songbird Initiative has an excellent, referenced page dedicated to the effects of global warming on birds. For an example of research on how mismatches between food requirements and food availability impact long-distance migrants, see this paper: Avian population consequences of climate change are most severe for long-distance migrants in seasonal habitats. While this warm spell is a weather event, it is indicative of the problems associated with a changing climate.

Here in spring 2012, things are already seriously out of whack. At this point, the best we can hope for is a return to much cooler weather, but without hard freezes or measurable snowfall.

Update:  Only four days later, we have had a freeze in southeast Michigan. Meteorologist Jeff Masters notes that it probably caused tens of millions of dollars of damage to Michigan fruit crops. Fortunately, it was only a single night, but we have a couple of months yet to go. Masters also lists other significant freezes -- including the one in 2007 which occurred in April. This preceded one of our poorest fall banding seasons, and I also discussed it in my summary of the spring 2008 survey season.

Thursday, March 22, 2012

Early Neotropical migrants (?)

With the exceptionally warm weather this March, I have been seeing quite a few reports of early migrants. I'm not too surprised to see early reports of species that winter in the U.S. (short-distance migrants). This is probably due to both favorable weather and the fact many more people are outdoors this year looking for birds. But reports of Neotropical (long-distance migrants) deserve more scrutiny. What follows is a version of a message I sent to our local birding listserv.

What are we to make of reports of Neotropical migrants arriving many weeks ahead of schedule? Why would these birds, wintering in the tropics with no "knowledge" of an early spring here, be arriving so early? The migratory movements of these birds are typically triggered by photoperiod.

For a Wood Thrush, for example, to be present in Michigan right now means that it departed its Central American wintering grounds in mid-February. Recent studies have indicated Wood Thrushes take about a month get here. The average arrival date here in southeast Michigan (based on 16 years of data) is May 1, so the typical departure from Central America is early April. While favorable weather patterns can accelerate migratory flights, the birds have to be on the move to begin with.

There are many things we still don't know about the interactions of weather, climate, and birds. Yet it seems hard to conceive why so many individuals of various species (and for us to find even a handful having survived to arrive in Michigan, the starting number would have to be larger) would begin migrating so prematurely. The annual cycle of birds has been intricately choreographed through evolutionary time. Remember, these birds have to spend a period of time (also coincident with resources in the tropics) gaining weight in order to migrate north, just like they do to go south in fall.

While the data is not infallible, an excellent assessment of where migrants are currently being located can be found at eBird. Go to Explore Data, Range and Point Maps, choose a species, and specify March to March, current year (direct link here). There have been only five reports of Wood Thrushes in the U.S. so far this month. Most are still in Central America.

I suspect that some (most?) of the Neotropical migrants being reported at northern latitudes, if accurate, may actually be birds that did not migrate last fall and managed to survive the very mild winter. Black-throated Green Warbler and its close relatives, orioles, and tanagers, for instance, are occasionally reported in winter. I've also given some thought to the fact that every year there may be a few exceptionally early migrants which routinely do not survive jumping the gun that might be having more luck this year. Still, this is probably pretty rare and might be more applicable to short-distance migrants.

At any rate, just because it's warm outside doesn't mean we can expect birds too many weeks ahead of  schedule. When they do arrive, detection and viewing this year will be greatly diminished by leaves -- this is a good year to learn your bird songs!

Update: Marshall Iliff, one of the eBird coordinators at Cornell, has written a couple of long but excellent posts on the Massachusetts bird list regarding early arrivals, including hummingbirds. He's someone who has a vast experience in examining migration patterns through his work. I strongly encourage you to at least read through this one. An earlier post deals more with common early migrant ID problems.