Neotropic Cormorant: A new Wayne County species

Birder Robert (Bobby) Irwin found a Neotropic Cormorant (just assigned to a new genus, and now Nannopterum brasilianum) off Humbug Island at the Detroit River International Wildlife Refuge on 28 June 2021. The eBird checklist with photos is here. As of 19 September 2021, it was still being seen, at least sporadically.

This identification is not an easy call. I happened to have visited the Refuge the previous day, one of the first times I have returned after spending years doing bird and insect surveys for the USFWS prior to the Refuge opening to the public. Various habitat modifications have resulted in a nesting colony of Double-crested Cormorants just north of the new fishing pier, with nearly 30 nests that I could see. Most of the young have fledged, so there were dozens of cormorants in the trees, flying around, and in the water, all in various plumages. Neotropic Cormorants are smaller than Double-cresteds, have longer tails, and different plumage on the face, but these differences are not always obvious, especially when the birds are moving around or distant. Kudos to Bobby for picking this one out.

As you can see from the range map, this bird is well out of range. However, they are known to wander a lot, and there are a number of Michigan records, mostly from the past few years. In fact, there is a pair nesting at Lake St. Clair Metropark in Macomb County right now! 

I have maintained a comprehensive Wayne County checklist, including historical records, for many years. By my accounting, this makes species #352 for the county, of which 9 are extirpated/extinct, hypothetical, or not "countable." 

Rockwood CBC: Lots of Refuge properties

Dawn at Humbug, looking from Jefferson Avenue toward the Trenton Channel Power Plant.

Since 2004, RRBO has been participating in the Rockwood Christmas Bird Count (CBC) by surveying the Humbug unit of the Detroit River International Wildlife Refuge (DRIWR). Last year I gave a little background on this count and our coverage of Humbug. This year, my husband and I once again counted at Humbug, but we also made whirlwind stops at five other units of the DRIWR that are within the Rockwood count circle. Several are fairly new units that are under restoration and the USFWS wanted to see if waterfowl were using them. Since the units are not open to the public and we have a special use permit for various projects, we offered to give them a look. Although it rained on Christmas Day, the next day most standing water had refrozen, limiting waterfowl use. That was probably not a bad thing. If the water had been open, we'd still be counting. As it was, this was more of a reconnaissance mission. Now we know the logistics, and can make recommendations on how the units should be covered in the future. We ended up walking over ten miles, but only tallied 44 species, owing to our quick work at most of the units and drive time between them. It was nice to see a total of 10 Bald Eagles at 4 of the 6 units. A Killdeer at the Humbug unit was probably our best bird. Great Blue Herons are always found in good numbers at Humbug, since there is always some open shallow water there due to discharge from the Trenton power plant just north of the property. We had 49 herons at Humbug, close to our record of 53 in 2004. We had another 19 roosting around the old quarry pond at the Gibraltar Bay unit on Grosse Ile (more on the units below). Sparrows in general seemed sparse, although we had two Fox Sparrows at the Brancheau unit. All of our 148 American Robins were at Humbug, feeding on Common Buckthorn, honeysuckle, and perhaps some rose hips. We completely missed any blackbirds, Carolina Wren, Cedar Waxwing (also missed by all other teams on the American portion of the count), and, sadly, American Crow. Very few crows were found on the count; this species does not seem to be recovering from West Nile Virus. Here is a run-down of the units. 

• The Humbug Marsh unit is in Gibraltar and Trenton. At least half of the northernmost section was rehabilitated over the summer, and was either unvegetated or iced over, making that part quick work. I've attached a number of photos to this route, so hover over the map, and click on the first icon on the right to go into slideshow mode. We had 29 species here.
• The Gibraltar Wetlands unit is very near Humbug, behind the high school at Jefferson and Woodruff Road in Gibraltar. Since it was frozen and we only had a few birds there, I did not include this in EveryTrail.
• The Gibraltar Bay unit is the former Grosse Ile Nature Area (and a one-time Nike missile site) at the south end of Grosse Ile. We mostly went for waterfowl. 22 species.
• The Fix unit was the furthest south we traveled, and is adjacent to the Fermi nuclear power plant in Monroe Co. These old farm fields have been planted with prairie and grassland vegetation, but were unvegetated this winter. We had 15 species here, including our only Winter Wren. More info here.
Walking a muddy dike at the Fix unit, with the cooling towers of the Fermi nuclear plant as a backdrop.

 
• The Brancheau unit is north of Fix, on the other side of Swan Creek. These fields will also be planted for wildlife. A pump system has been installed to bring in water from Lake Erie so the fields can be managed for waterfowl or shorebirds. 17 species.
• The Strong unit is just south of Pointe Mouille State Game Area. It also has old farm fields, and a large wetland bordered by dikes. The main dike is tall and grassy, with fields and woods on one side, and the wetland on the other. In many places Phragmites makes it hard to see into the wetland. We had our Fox Sparrows here, along with most of our American Tree Sparrows. We also had a Sharp-shinned Hawk, less common than Cooper's Hawks here in winter. 24 species.

The final dike walk of the day, this one at the Strong unit.

Realistically, covering all these units effectively takes more than one group of people. In the future, we will probably continue at Humbug and then concentrate on Gibraltar Wetlands and Gibraltar Bay.

Five years of Christmas Bird Counts at Humbug

It's hard to believe that I have been doing bird surveys at the Humbug Marsh Unit of the Detroit River International Wildlife Refuge for five years. The Refuge was established in 2001 and includes a patchwork of properties along 18 miles of the lower Detroit River. The 410-acre Humbug Marsh unit, straddling Trenton and Gibraltar, was acquired in 2003 after a lengthy battle with developers. It represents the last mile of undeveloped land on the U.S. mainland side of the Detroit River. RRBO's partnership with the U.S. Fish & Wildlife Service and the Refuge began in 2004. Although this area is within the Rockwood Christmas Bird Count (CBC) circle (itself established in 1974), it had never been accessible for bird surveys. Since 2004, RRBO has completed five CBCs at Humbug, as well as two North American Migration Counts, four years of Breeding Bird Atlas work, and two major insect surveys. December 27 was our fifth CBC at Humbug. The day started with very thick fog, making waterfowl counting difficult. Some years, much of the river is frozen and a lot of waterfowl gather in the channel between the mainland and Humbug Island. This water stays open due to the warm discharge from the Trenton Power Plant just upstream. Humbug Island is to the right in the photo below, but the thick fog bank in the center is completely obscuring Grosse Ile. The day ended up breezy and very balmy, with record-breaking temperatures over 60F. This melted much of the snow we'd had in the previous weeks. In the southern portion of the Refuge, an old road was removed over the summer. In its place: thick muck and deep water-filled ruts covered in sloppy snow and thin ice. We were unable to fully cover this area because we just couldn't walk through it. Still, we had a nice adult male Sharp-shinned Hawk at this spot. The Humbug Marsh Unit is not yet open to the public. When my husband Darrin O'Brien and I do the CBC there under RRBO's special use permit, we are alone to walk the many acres. There are a few new, formal trails, but usually we just have to follow deer trails or bushwhack. The northernmost part of the property is an old brownfield. It's quite open and in the winter has the fewest birds. Here I am traipsing across the middle of it. We had 47 species at Humbug for the day. Highlights included two Bald Eagles, a Yellow-bellied Sapsucker, one American Crow (the first on the Humbug count in five years!), three Brown Creepers, one Winter Wren, five Golden-crowned Kinglets, three Hermit Thrushes, an Eastern Towhee, a Purple Finch, and six Rusty Blackbirds. The rusties were also the first we've had there in winter, and we were happy to see them because it is a species in significant decline. We had over 200 American Robins, and over 50 White-throated Sparrows (Humbug is a great site for wintering white-throats). In the midst of it all, I was able to take a short break on one of the new benches along the river. The cumulative species total for the five years is a respectable 74. Only 16 have been seen all five years, in large part due to the variable mix in waterbirds influenced by river conditions. Unusual species have been Gray Catbird in 2005 and Common Yellowthroat in 2007. The species total will undoubtedly grow as habitat is restored and, when the unit is fully open to the public, the number of participants on the count increases. January 1 is the date for the Detroit River CBC, which includes Dearborn. I'll post a report on that count next week!