Nov 6, 2019 | Featured Web Article

Group Feeding Strategies Among Backyard Birds

Mixed flock feeding is the strategy you’re most likely to see playing out in your backyard in late autumn and winter.
Share:

With fall comes the end of the breeding season and the return of flock feeding among backyard avifauna. Birds that spent their spring and summer in solitude or paired with a mate while tending their clutches are banding together into groups. You might be noticing larger numbers of crows, starlings, finches, or robins in and around your backyard. Did you know that there are three unique flock feeding strategies?

Mixed Flocks

Mixed flock feeding is the strategy you're most likely to see playing out in your backyard in late autumn and winter. Birds that spend the breeding season defending their territories from potential competitors group together with several individuals of other species when the weather turns cold. The newly formed flock eats together as it moves through an area and may revisit the same spot multiple days in a row.

Between 12 and 100 individual birds form a mixed flock, which might include titmice, chickadees, juncos, kinglets, house finches, goldfinches, nuthatches, pine siskins, and downy woodpeckers. Of course, your home region will determine what species make up the mixed flocks visiting your backyard.

Commensal Feeding

Commensal feeding occurs when birds of one or more species follow another bird to eat what that bird has left behind. For example, bluebirds and nuthatches follow woodpeckers to catch whatever insects the woodpecker might have missed. After a pileated woodpecker removes a tree's outer bark, hairy woodpeckers fly in to see if there are any leftover bugs near the surface to consume. Warblers, hummingbirds, and kinglets benefit from the sap that oozes into the wells that sapsuckers drill into tree trunks.

Typically, the birds that benefit from commensal feeding do so without negatively impacting the other birds that they follow. Beyond the backyard, this behavior occurs among American coots swimming behind mallards, common ravens trailing golden eagles, and even cattle egrets feeding on the insects attracted by grazing mammals. Unlike mixed flock feeding, commensal feeding occurs throughout the year.

Guilds

Another year-round feeding strategy, feeding guilds form when species from a variety of taxonomic groups consume the same resources in a similar manner. Hummingbirds and butterflies may form a guild of diurnal nectar feeders. In the Southwest, ants, rodents, and desert sparrows may create a seed-eating guild.

You might have a guild composed mostly of insectivorous birds that hunt for insects in tree bark and among foliage in your backyard. This guild will exist throughout the year, but its membership may change as migrant bird species come and go.

Of all of the drummers in the woods, none is more interesting or has more impact on its neighbors in the web of life than the sapsucker. Check out some intersting facts about these fascinating birds!

  • Four species of sapsuckers reside in North America:
    • Yellow-bellied is the most widespread, nesting from eastern Alaska, across Canada to the Atlantic coast, and south into the Appalachian mountains, and wintering from western Texas to Cape Cod to Panama and the Caribbean Islands.
    • Williamson's and red-naped sapsuckers nest throughout the West east of the Cascade Range, and winter in the far Southwest and in Mexico.
    • Red-breasted sapsucker is found west of the Cascade Range, from southern Alaska to Baja California.
  • Until 1983, red-naped and red-breasted sapsuckers were considered the same species as yellow-bellied.
  • Sapsuckers are found only in North and Central America.
  • All four species of sapsucker are relatively slender woodpeckers, with relatively long wings.
  • Adult sapsuckers (except the female Williamson's) have a bold white wing stripe.
  • Unlike other woodpeckers, sapsuckers bore holes in trees not to find insects, but to cause sap to flow, which they lap with their long tongue. They don't really suck sap!
  • Sapsuckers feed primarily on sap, but also insects, especially those attracted to the sap.
  • Tidy, evenly spaced, horizontal or vertical holes on trees are evidence that a sapsucker has been working.
  • Because sapsuckers feed on living trees, they are often considered a pest species.
  • Sapsuckers prefer tree species with thin bark, such as birch, but they will bore into many types of trees.
  • Most trees survive sapsucker holes, but they can cause severe tree damage and mortality. Certain tree species are more adversely affected than others. A study found that 67 percent of gray birch trees damaged by sapsuckers later died from their injuries; 51 percent for paper birch; 40 percent for red maple; 3 percent for red spruce; and 1 percent for hemlock.
  • All sapsuckers are quiet in winter.
  • Sapsuckers are known to visit nectar feeders intended for hummingbirds and suet feeders.


What do you think? Tell us!

comments powered by Disqus

New On This Site

The Latest Comments