Common Redpolls, feeding on Black Alder

 

A male American Goldfinch (Spinus tristis) feasts on the seeds of Black Alder (Alnus glutinosa). Much as I love goldfinches, this was not the species that made me visit a grove of invasive nonnative alders. The main reason was a close relative of the goldfinch, and a species far scarcer in Ohio.

I made this trip - and these images - back on February 15. In part because of my curiosity about the plant that my target birds were feeding on (avidly!), I wanted to write about the experience. It's just taken me this long to get around to it.

A female Common Redpoll (Acanthis flammea) sits among the abundant fruits of Black Alder (sometimes called European Alder). She is fluffed like a puffball in the frosty temperatures - low-20's F as I recall. Nippy as that may seem, it is nothing for these finches of the far north.

She was part of a flock of perhaps 75 birds that had been in residence at Willow Point Wildlife Area on Sandusky Bay, Erie County, Ohio, for several weeks. There is no question that the alder was part of the allure for them. I spent about two hours with the group, and all they did while I was there was feast on alder fruit. In the photo above, the cone-like structures are the pistillate (female) catkins. They produce the seeds that were so coveted by the finches. The pinkish slender elongate structures are the staminate (male) catkins. Alders are in the birch family (Betulaceae), and redpolls are quite fond of feeding on plants in that group.

However, I would not have guessed they'd work over Black Alder, a small tree that always makes me cringe when I see it. This Eurasian species was brought to the New World long ago, and has been planted ornamentally, and as erosion control. I suspect wildlife agencies may have at one time planted it at one time, too. I don't know how the alder got to this site, but it is thriving and has formed fairly extensive dense stands.

A redpoll dangles acrobatically to better pop cone scales off and access seeds. Look at those little leggings! Redpolls are a delight to watch, and a quiet observer can usually do so at close range. The small finches can be incredibly tame. At times, birds were coming to within five feet of me - well inside my lens's minimum focusing distance.

It was snow-covered, and the dark cone scales littered the ground under feeding areas. Similar to crossbills, the flock was mostly silent when busy with feeding, and showers of scales rained down. When they took to the wing, it was a riot of redpoll vocalizations, and the flock could not be missed.

A major issue with Black Alder is its dense growth. As the plants mature, they shade out the ground below and greatly reduce or eliminate native flora. This is particularly vexing at this site. The southern shore of Sandusky Bay is known to harbor populations of the federally threatened Prairie White-fringed Orchid (Platanthera leucophaea) and the site where these alders are looks fine for that spectacular orchid (See HERE for photos of the orchid and one of its pollinators). But not when overrun by alders.

A striking male Common Redpoll looks like it got pelted with raspberries. The showy little songbird was taking a brief rest and look-around before diving back into the alder cones.

This tale illustrates that even the most pernicious of weeds can have a plus side. There's no question that these redpolls found favor in the fruit, as did the goldfinches. Does that justify planting Black Alders in wild places for erosion control or wildlife? No, in my opinion. Any wildlife that is lured by the invasive tree certainly does not need or depend on the alder. And the diversity of native flora cast out by the alder invasion serves far more ecological functions.

But I will admit that in winter - especially winters with redpoll irruptions - I will pay more mind to Black Alders when I see them.