Dearborn has an interesting winter roost of Black-crowned Night-herons (Nycticorax nycticorax) at a pond near the Rouge River inside the Ford Rouge Plant complex (scroll down in this post for a map and description). Access to this site is restricted, but Mike O'Leary as a former Dearborn police officer and current Ford employee has been able to periodically survey birds, and consequently the night-herons get counted at least once a year on January 1, the day of the local Christmas Bird Count. They were first recorded on the count in the 1980s, and then were nearly annual beginning in 2003. Peak numbers occurred around 2006-2009, when over 30 were found each year. Numbers have averaged much lower in recent years, often around a dozen. They can be very hard to see tucked into the Phragmites and other vegetation, not moving because as their name indicates, they are not really active during the day.
On 23 December 2020, Mike was scounting for the upcoming count when he tallied 8 night-herons at the ugly pond. It wasn't until he was looking over his photographs that he noticed one preening (or sleeping) bird was standing on one leg, and the other leg sported a color marker! When he sent me the photo, I immediately knew this wasn't a new marker, because the letters should have been dark black on a bright yellow band (example here).
The invisible leg would be the one with the standard USFWS metal band with its identifying 9-digit number. However, there is a way to report just a color marker at the federal Bird Banding Lab website, which Mike did immediately.
|Black-crowned Night-heron in Dearborn, MI. Inset shows color marker.|
Mike received a prompt response that the bird had originally been banded as an adult of unknown sex on 29 May 2014 under the banding permit of colonial waterbird expert Dr. Francie Cuthbert at the Detroit Zoo in Royal Oak, MI.
The Zoo has had a colony of nesting Black-crowned Night-herons since around 1997, when the first juveniles were found there by Doris Applebaum; this was the first documented breeding of this species in Oakland County. At least 6 nests were found the following year. In recent years the Zoo has had as many as 50 pairs. This is one of the significant colonies in the Great Lakes and I believe the largest inland colony in Michigan (see a map of colonies on page 12 of this Audubon Great Lakes waterbird report). These birds have been banded and/or color-marked for a number of years.
Once again, Mike comes through with a great, interesting bird find in Dearborn!
Applebaum, D. 1998. Oakland County nesting of Black-crowned Night-Herons. Michigan Birds and Natural History 5(1):12.
Applebaum, D. 1999. Follow-up on Black-crowned Night-Herons at the Detroit Zoo. Michigan Birds and Natural History 6(1):20-21.