Wednesday, February 28, 2018

Confluence Pond Migrants

"The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking."

― Albert Einstein

Red-winged Blackbird

Spring migratory birds are returning to Wisconsin in massive numbers on account of recent mild weather. There will be northbound flocks whenever weather is appropriate (south winds) from now until the middle of June. It's the best time of the year! Red-winged Blackbirds have moved into the conservancy's fields and wetlands and are already aggressively defending territories with song.

Participating in spring migration as a birder is sort of like re-watching a favorite movie, over and over. Though the overall plot and story arcs are basically the same, subtle differences in timing, numbers, and responses to habitat changes vary from one year to the next. The players change, too. Sadly, in many cases there are fewer actors as well as roles to play. But such subtleties are partly what fuels the desire to learn for those of us who consider ourselves citizen scientists.

Sometime during winter, the City of Middleton cut down and mowed all of the willows, cattails, and other vegetation surrounding the confluence ponds of Pheasant Branch Creek. It kind of looks like a nuclear bomb went off over the area ― perhaps I'll share before and after shots in a future blog post. Anyway, it will be interesting to see how various species respond to this change.

Birds I believe will be most impacted include:

Wood Duck
Blue-winged Teal
Green-winged Teal
Green Heron
Virginia Rail 
Wilson's Snipe
Spotted Sandpiper. 
Willow Flycatcher 
Marsh Wren
Yellow Warbler
Swamp Sparrow 
Red-winged Blackbird 

In response to an inquiry I made, Brad Hopwood, Operations Manager for Middleton, wrote:

"The issue that we have been having with them, is that they are growing out of control and we have no way to maintain them. They also have been causing water blockages throughout the storm water system causing flooding upstream. With us trying to get the storm water management under control city wide, this was one of the areas of concern."

As undesirable as the willows apparently are, the habitat has attracted a respectable variety native birds during the breeding season. Because many bird species exhibit high nest-site fidelity (philopatry), they'll fail to find desirable habitat upon their return. Then they'll face a new challenge: finding habitat that hasn't exceeded carrying capacity. This can be a pretty tough job for some birds. In a way, it's kind of a cruel trick to play on birds that were trying to get established at this particular parcel of habitat.

I always thought the confluence ponds were part of Middleton's conservancy lands. Though some Middleton maps show it defined as such, I received a clarification from Mark Wegner, Middleton's Forestry and Conservancy Lands Director:

"There has been a history of areas of overlap between City departments; the confluence pond area is one such spot. The pond area has always been Public Works, the trails Public Lands. The vegetation around the pond has been a grey area; Penni had taken upon herself to make this area and many others more native and prairie. One of the major components of this plan update is to identify priority work areas as well as determine actual areas of responsibility for us in Public Lands."

Hooded Merganser

To be sure, the confluence ponds have prevented sediment and lake-fouling phosphorus from reaching Lake Mendota, but it would be nice if the habitat could be more effectively managed so it won't negatively impact returning migratory birds that want to nest there.

Belted Kingfisher

Sandhill Crane

Bugling! It's such a pleasant sound, even at close range!

After finishing up at the confluence ponds, I decided to hike the creek corridor trail at night. The moon was so bright that I didn't need a flashlight to see my way. Clouds were quickly moving overhead, so I thought of a fun photography project to do. These are all 30-second exposures with my camera tripod-mounted. The orange tint on the clouds comes from Middleton's lights.

Confluence Pond & North Fork Marsh, Dane, Wisconsin, US
Feb 27, 2018 5:00 PM - 6:30 PM
28 species

Greater White-fronted Goose
Canada Goose
Wood Duck
Hooded Merganser
Great Blue Heron
Red-tailed Hawk
Sandhill Crane
Ring-billed Gull
Mourning Dove
Belted Kingfisher
Downy Woodpecker
American Crow
Horned Lark
Black-capped Chickadee
American Robin
European Starling
American Tree Sparrow
Dark-eyed Junco
White-throated Sparrow
Song Sparrow
Northern Cardinal
Eastern Meadowlark
Red-winged Blackbird
Common Grackle
House Finch
American Goldfinch

All images © 2018 Mike McDowell

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