Wednesday, January 1, 2014

A Northern Cardinal eating red honeysuckle berries in the snow...sustenance or an "ecological trap?"

A couple weeks ago, while the snow was still fresh, Rick and I headed over to the Little Miami River to walk in the fluffy whiteness and look for birds. We saw White-breasted Nuthatches, Carolina Chickadees, Downy, Pileated, and Red-bellied Woodpeckers, Golden-crowned Kinglets, White-crowned and White-throated sparrows, Northern Cardinals, Blue Jays, Eastern Bluebirds, and a Red-shouldered hawk. We even saw a solitary Pied-billed Grebe swimming and diving in the river near the Lebanon cut-off bridge. It really was a winter wonderland, and we had the place to ourselves! All the birds were chatty (except the grebe), and they all were busy searching for food to help fuel them through the snowy day and upcoming night. At one point, we stopped and watched a male Northern Cardinal eating bright red berries from the frozen branches of an Asian Honeysuckle bush. If you look at the photo below, you can see berry pulp and skins still plastered to his bill. "At least these invasive bushes are good for something," I said to Rick...

A bright red Northern Cardinal was happy eating the bright red berries on an Asian Honeysuckle bush. 

When I got home, I googled, "Are Asian Honeysuckle berries good for cardinals?" I knew the berries had helped American Robins expand their range to the north, but I didn't know if the berries had helped Northern Cardinals. Along the Little Miami River, Northern Cardinals love the dense thickets that border the trail, and they claim the territory for their nesting sites in the spring, so they seemed to like the plant, but was the plant good for them? The first article to pop up in the search was written by John Carey on the National Wildlife website titled "Nonnative Plants: Ecological Traps; Offering alluring habitat for songbirds, exotic plants may actually decrease the animals' long-term survival fitness" (click here for the article). The article had a Northern Cardinal munching on bright red Asian Bush Honeysuckle berries, much like our little cardinal was doing. Uh...oh...

Asian Honeysuckle berries create an artificial indicator of health
Ecologist Amanda Rodewald of Ohio State University has been researching the affects of invasive honeysuckle on Northern Cardinals. Basically, the berries of Amur honeysuckle and other Asian invasive species might help cardinals get through the winters now, but 70 generations from now? Seems the berries artificially create bright red, healthy-looking males. Females usually chose the most colorful males as mates because bright red plumage indicates the birds have been eating berries packed with nutrients to make them strong and carotenoid pigments that make the feathers red. Asian honeysuckle berries contain plenty of pigments to color the feathers, but they lack the protein and fat the cardinals need to stay healthy and fit. So the bright "dye job" that results from a diet of Asian honeysuckle berries is misleading, and females may choose males that are not the healthiest. As a result, the couple will fledge fewer offspring, which over time could hurt the population.

Asian Honeysuckle bushes are an "ecological trap" for nesting cardinals
In another study, Rodewald uncovered an additional danger to Northern Cardinals. Asian honeysuckle bushes leaf out first among all forest plants. Northern Cardinals are early nesters, so the fittest males nest earlier than other birds by nabbing nests in the dense branches of the green and leafy honeysuckle bushes. Even though these sites appear to be the best, they aren't, and cardinals that nest in honeysuckle have a lower fledge rate than the less-fit cardinals who have to wait to chose "less desirable" sites in native trees and bushes. The earlier nesters fledge 20% fewer young, which means the healthiest birds are not reproducing at a normal rate. Why? Because cardinals nesting early in invasive honeysuckle are about the only birds nesting in the forest at that time, so they become marks for predators because they are easier to find. Rodewald concludes "breeding in honeysuckle seems to flip natural selection. It is a kind of ecological trap." (Check out the entire article for details on Rodewald's research and additional findings by other researchers.)

Eliminating non-native invasive plants from your yard...
I've been battling invasive honeysuckle from my yard for years. It's just about gone now, and I've replaced it with several varieties of native viburnum bushes, Staghorn Sumac, holly bushes, and others. The National Wildlife Federation (NWF) advises trying to eliminate the invasive shrub from your yard. Botanist Bruce Stein, National Wildlife's director of climate change adaptation writes, "While many nonnative plants are fairly benign, others can be ecologically destructive. We need to pick our battles wisely by figuring out which ones we can live with and which, if left unattended, will undermine our ecosystems.”

Click here for a pdf by The Ohio State University titled, "Controlling Non-native Invasive Plants in Ohio Forests: Bush Honeysuckle," for a description of Amur, Morrow, and Tartarian honeysuckle (Lonicera spp.) and recommendations on how to get rid of it.

Click here to learn more about invasive species and how NWF is working to stop their spread.


13 comments:

~mel said...

Beautiful cardinal photo ~ there's just something about them with a little snow that sure does make their color POP!
You said you had planted some staghorn sumac ~ I have that growing on the edge of my yard. I love it ... one of my favs :)

Montanagirl said...

Kelly, that's really interesting reading! And those male Cardinals are so beautiful.

Cherrie said...

He's so beautiful, it's sad that the berries are not good for them.

Elaine said...

Love the cardinal against the snow! Interesting how an invasive plant can be so destructive, not just now but many generations down the road. We have problems with invasive species here too, and the ones I spend the most time pulling are bird vetch and sweet clover. The bird vetch is particularly bad as it curls up and around other plants and chokes them off. Amazing how fast they can take over an area too.

kestrelart said...

I guess females that are programmed to select mates on different criteria will outbreed those that select on colour, and those programmed to nest early will become rarer or perhaps nesting early will disassociate from other markers of fitness. Evolution in action.

Lois said...

I want to say this carefully because I don't want to be offensive, but I have a concern about so much worry over "invasive species". Isn't it natural that ecology should change and evolve? Is it possible that some of the worry is misplaced? I hope I am not wrong in thoroughly enjoying the eastern blue jays, common loons and orioles that I see so much more often here in North Idaho. It is a subject I would love to read up on if you have any recommendations.

Kelly said...

Lois...click the link to the article I've listed in the post. In it you'll find a biologist who feels invasive plants are not a problem. You can probably look him up and see what he has to say.

Mary Ann Gieszelmann said...

Very interesting, Kelly. It certainly shows that things may not be as straightforward as they seem.

Atanasio Fernández García said...

Hi Kelly! It is very interesting the ecological impact of invasive plants on the species. I don't know a similar example in Southern Europe, at least in birds. Happy new year!

Steve Borichevsky said...

Wow, I had no idea! On our lot which is on the edge of the Great Salt Marsh and woodland, we have been overrun by Buckthorn. My landlord is working on irradiating that species. I'll have to check to see if we have any Asian Honeysuckle.

Kelly said...

...thanks, everyone for the kind words. Who knew these berries were not the best source of nutrition for Northern Cardinals! Thank goodness scientists and researchers do their work. I really enjoyed reading about the studies of ecologist Amanda Rodewald (of the Ohio Stat University!)...and I'm glad I've been working to get the invasive out of my yard!!

Eddy TheDog said...

It's subjective Lois...

A honeysuckle mono-culture is great if you love honeysuckle and awful if you love any other plant.

Do you love emerald green ash borers or ash trees.

Do you fish with the common invasive earthworm or do you fish with crickets?

When you fish, do you fish for flying carp or bluegill?

Do you love the occasional blood root or a uniform drift of blooming celandine?

Do you love invasive dandelion for the wine or native milkweed for the butterflies?

Garlic mustard salad or poke salat?

The long term effects of the columbian exchange are still playing themselves out. Sometimes there's a lone locust sapling forcing its way up and above a dense thicket of honeysuckle. It'll grow and slowly drown out some of the honesuckle thereby making room for bloodroot, trillium, or a bunch of garlic mustard. Invasive's, by their very nature, change an ecosystem. Some existing members of the ecosystem benefit from the introduction of an invasive, other's do not. The woodpeckers might be happy that the emerald ash borers are here, but the ash trees are not.

The honeysuckle, ash borers, and celandine are of little value to me as a human but I can eat the garlic mustard, fish with the earthworms, and make wine from the dandelions. If the honeysuckle drowns out a wild pawpaw I could have eaten, I've suffered a net loss as a result of an invasive.

There is only one thing that benefits all members of an ecosystem equally... more peanuts.

Eddy TheDog said...

It's subjective Lois...

A honeysuckle mono-culture is great if you love honeysuckle and awful if you love any other plant.

Do you love emerald green ash borers or ash trees.

Do you fish with the common invasive earthworm or do you fish with crickets?

When you fish, do you fish for flying carp or bluegill?

Do you love the occasional blood root or a uniform drift of blooming celandine?

Do you love invasive dandelion for the wine or native milkweed for the butterflies?

Garlic mustard salad or poke salat?

The long term effects of the columbian exchange are still playing themselves out. Sometimes there's a lone locust sapling forcing its way up and above a dense thicket of honeysuckle. It'll grow and slowly drown out some of the honesuckle thereby making room for bloodroot, trillium, or a bunch of garlic mustard. Invasive's, by their very nature, change an ecosystem. Some existing members of the ecosystem benefit from the introduction of an invasive, other's do not. The woodpeckers might be happy that the emerald ash borers are here, but the ash trees are not.

The honeysuckle, ash borers, and celandine are of little value to me as a human but I can eat the garlic mustard, fish with the earthworms, and make wine from the dandelions. If the honeysuckle drowns out a wild pawpaw I could have eaten, I've suffered a net loss as a result of an invasive.

There is only one thing that benefits all members of an ecosystem equally... more peanuts.