Banding summaries: 1999-2003

Spring 2003

Spring banding 2003 took place on 37 days from 14 April to  8 June.  Nets were open an average of 5 hours per day with  an average of 20 nets (12 meter equivalent1).   Here is a summary of our results:

Spring 2003 Previous
spring mean
New birds 831 557
Total handled2 1090 700
Species 70 63
Birds per 100
net hours
30 41.

Sometime in May, we surpassed the 20,000 bird mark.  It took us seven years to reach the 10,000th bird, but only five more to get to 20,000, reflecting the increased effort of our dedicated volunteers.  Thank you to all!

One of 5 Blue-winged Warblers banded this spring.

Season chronology
April was uneventful, but May 1 brought a weather system and lots of birds, marking the spring arrival date for over a dozen migrant species.  At this point we realized that it was going to be a great season for sparrows — region-wide, people noted higher-than-usual numbers of White-throated and especially White-crowned Sparrows. By the end of the season, we had banded 102 White-throats.  Our spring mean is 29, and the most we’ve ever done in a spring season was 47.  We banded good numbers of White-crowned Sparrows as well, despite the fact the nets are not in optimal habitat for this species.  However, our surveys tallied White-crowns in very large numbers.  They typically depart southern Michigan by May 20, as they nest in northern Canada, but we captured our final White-crown on the last day of the banding season — June 8!  The rather elusive Lincoln’s Sparrow was also banded in record numbers, with 37 banded being a 252% increase in the previous spring mean.

A sparrow provided our “best bird of spring,”  a Clay-colored Sparrow banded on May 6 (right).  This was likely a different individual than was seen on May 1-2.   This species is rare in migration, and the majority of Wayne County records are from right here at RRBO.

The surprise bird of the season was an American Bittern on Fairlane Lake on April 26.  Seen by a local bird group here on a field trip, it was one of only a few records in Dearborn over the last 25 years.

After the good influx of early migrants the first week in May, the jet stream and weather patterns ceased to cooperate.  Over 80% of our banding days lacked winds with a southerly component, which usually promote migration.  Birds were delayed in their arrival and moved through slowly.  The number of migrant birds we recaptured a day or more after initial capture illustrated the lagging pace of migration.  The mean number of migrant birds (species that only pass through our site on migration) recaptured during the spring seasons 1993-2001 is 9.6, and the mean stay was 2.8 days.  This year, we recaptured 40 birds which stayed 3.8 days.  The only other spring  we’ve had so many recaptures was last year — another cold, wet, and rainy season.  We’ll see what effects this has on nesting.

Same time, each year
We always enjoy welcoming back migrant birds banded here in a previous year.  This spring was no exception.  The oldest returning bird was a male Wood Thrush banded in 1995.  We recaptured him in 1997-2000, but missed him the last couple of years.  This bird is at least 9 years old, and has therefore made at least 9 round trips between Dearborn and Central or South America! For more on our color banded Wood Thrushes, go to our Wood Thrush project page.

A total of 129 Gray Catbirds have returned to UM-Dearborn since 1992.  The oldest bird to return this year was a bird originally banded in 1996, making him  at least 8 years old.   In all, 273 migrant birds banded here have returned in subsequent years, over half of them long-distance migrants that winter in the tropics.  Think of all the frequent-flier miles!

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  1. In order to compare different locations or years that may operate the same number of hours but with more or fewer nets, capture rate is calculated by “net-hours.” One net hour is one 12-meter net open one hour, or two 6-meter nets open one hour, etc.  This rate is often expressed per 100 net-hours for more manageable numbers.
  2. Total handled includes recaptures and birds released unbanded.

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