Feed the birds — tuppence a bag?

I was surprised to quite a sizable area in my local hardware store allocated to bird feed and feeders.  Feeding the birds is big business in the U.S. where a surprising 34% of households reported buying some bird seed in 2013 (according to U.S. Fish and Wildlife Service data).  That amounts to expenditures of $3.2 billion on bird seed and $1.1 billion on bird feeders! Hardly tuppence. Canadians apparently really love their backyard birds, because the same study showed that a whopping 61.5% of Canadian households bought at least some bird seed and spent the U.S equivalent of $800 million on it.

common redpolls at the feeder

Large flocks of Common Redpolls descend on thistle feeders in the winter.

But is all this bird feeding good for the birds?  How much do birds really rely on supplemental food provided by bird lovers?  Some say as little as 10-25% of the daily food intake actually comes from bird feeders — but these are estimates, not actual measures. There are surprisingly few studies on the subject, but I’ll summarize some of the salient findings of the few studies I found.

1. Supplemental feeding in the winter promotes survival, especially of weaker individuals in the population.  

house finches

A small flock of House Finches munched up the sunflower seeds, and then quickly disappeared. They might be making the rounds of all the neighborhood feeders.

This sounds like a good thing, but is it?  One of the primary tenets of natural selection is the “struggle for survival”, in which only the most fit continue their genetic legacy.  Weaker individuals are by definition less fit, more prone to disease and may, in fact, promote disease in an otherwise healthy population.  So, really, not such a good thing.

2.  Supplemental feeding promotes breeding success by advancing the date of the first clutch of eggs laid, and encouraging more birds to breed (provided there is space for them).

This also sounds like a good thing to promote.  Birds supplemented by winter feeding have higher levels of fat supplies in the spring and can commence their reproductive cycle earlier and with more vigor.  But, by doing so, they may actually get out of sync with the food supply on which the chicks depend for nourishment, and end up raising a clutch of weaker individuals — which would then be supplemented by backyard bird feeders, and so the circle goes round and round. In the U.K., researchers found that clutch sizes of the Blue Tit (a chickadee relative) were smaller and there was lower overall hatching success in populations that were supplemented with winter feed.

american-goldfinch-singing

Chickadees and Cardinals have started singing here already, before Feb. 1. The Goldfinches may not be far behind, after a winter of eating my banquet of birdseed.

Increased numbers of nesting birds of a particular species also increases the competition for food, meaning everyone gets less of everything.

3.  Supplemental feeding discourages migration and encourages northward expansion of some species’ ranges — which is great for us northern bird watchers, right?

This has been demonstrated for a few species, most notably the Northern Cardinal whose range keeps steadily expanding northward.  But  each morning I marvel that the little Yellow-bellied Sapsucker is still here in the backyard, pounding away at the suet, and I wonder if it eats anything besides suet.  That can’t be a good diet.

yellow-bellied-sapsucker

Just like clockwork, he/she shows up just as it’s getting light in the backyard to feast on some peanut butter suet.

I am not advocating here that we should stop feeding birds — that would really diminish the opportunities and enjoyment of winter photography around here, to say nothing of the enjoyment of just watching their daily activity.  But I do think we should practice restraint on the quantity of low-quality seed distributed and promote healthy nutrition by supplying fresh, dry seed that perhaps has some vitamin supplement. Moldly, old seed is definitely bad for bird health, as are moldy, old feeders that have layers of who-knows-what between bird beaks and the fresh seed.  So, with those cautions about the feed in mind — happy bird watching.

17 thoughts on “Feed the birds — tuppence a bag?

  1. Good points, all. The only caveat that I’d say is that, while it’s true that bird-feeding distorts birds’ regular patterns of mortality, nesting and migration – all of these things have always fluctuated with the environment – and like it or not – humans now create much of that environment. As long as the feeding is a consistent part of their environment, then I think it is a net good. I feed during January and February, because it’s a time of real stress and mortality for birds, and I figure they have enough problems with habitat destruction, pesticides, cat predation and so on – that tipping the balance back a bit is a good thing. And, of course, I like to see them!

    • That’s a problem for sure. As you may know, the numbers of Cooper’s Hawks are increasing, especially in urban and suburban areas, probably largely due to the number of backyard bird feeders. Vet clinics and raptor rehabilitation facilities are overrun with Cooper’s Hawks that have damaged themselves chasing after small birds near houses.

    • I figure we’ve interfered with nature so terribly already, this is a small way of making amends. And helps to say “sorry” to the birds for all the mortality caused by people who let their cats roam free…

  2. Provocative posting, Sue, which does a good job laying out some of the pros and cons of feeding birds. I don’t have a bird feeder, more because of the very small backyard of my suburban townhouse than for reasons related to bird survival.

    • Thanks, Mike. I, like many others I suppose, get carried away with the winter bird feeding, and I often wonder if I am really doing them a favor or not.

  3. In this area the birds have it easy. There is still maize lying in the fields where the heads have been broken and missed. The cabbage and brussel sprout tops are never attacked by hungry pigeons. We are completely selfish in attracting the birds to our patio feeding area here and honestly admit – it is for our pleasure. Amelia

    • Same here, Amelia. And each year I add new food or types of feeders in the hope of attracting a greater variety of birds. I guess I wrote that post to remind myself not to get so carried away with it. 🙂

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