Baffling Bird Behavior — Your Questions Answered

  1. What spring bird persistently sings, day and night?
  2. How long before robin eggs hatch, and when do the young leave the nest?
  3. Do Carolina wrens normally leave their eggs unattended?
  4. Can you identify the birds flocking around our chimney at nighttime?
  5. Why do American crows groom/massage/stroke each other?
  6. Why do large groups of blackbirds or American crows often attack a single hawk?
  7. How can I stop a woodpecker from pecking holes in my stucco house?
  8. Do large groups of robins indicate that a flock is migrating South for the winter?
  9. Do wrens eject young bluebirds from their houses?
  10. Do all birds mate for life?
  11. Do all birds migrate?
  12. Why do pileated woodpeckers peck holes in house siding, and is there a practical way to discourage them?
  13. A wren in my backyard is killing bluebird and tree swallow nestlings. What can I do to help protect these birds?
  14. Why does the Ovenbird sing in sudden bursts after nightfall?

 

 

1. What spring bird persistently sings, day and night?

A: Your bird is most likely to be a northern mockingbird. Don’t worry, male mockingbirds only perform this nocturnal singing in the spring and summer during the time of the full moon. Try running an electric fan (to create a buffer of sound) and using your earplugs on those nights when the male mockingbird is singing. Having a mocker around is a good thing-you might even consider yourself lucky!

An excellent source for backyard bird identification is An Identification Guide to Backyard Birds.

2. How long before robin eggs hatch, and when do the young leave the nest?

A: Robins incubate their eggs for 12 to 14 days. Once hatched, the nestlings remain in the nest for another 14 to 16 days before fledging.

3. Do Carolina wrens normally leave their eggs unattended?

A: Yes, this is normal when the female is completing the clutch of eggs. Female songbirds typically lay one egg each morning for four to five days until the clutch is complete. Then they begin incubating the eggs. This way the eggs all develop at the same time and hatch synchronously. For more information on nesting birds, get a copy of A Guide to Bird Homes.

4. Can you identify the birds flocking around our chimney at nighttime?

A: The birds are appropriately called chimney swifts, named for their preferred nesting location, inside chimneys. During fall migration small flocks of swifts gather into large communal roosts numbering hundreds or even thousands of individuals. Your chimney appears to be a migrating roost for chimney swifts. For more information, I suggest you check your local library for a good bird book. In most good bird books you’ll find a profile of the chimney swift that will explain the species’ natural history and behavior.

5. Why do American crows groom/massage/stroke each other?

A: Ornithologists call this allo-preening and it occurs in a wide variety of birds including small finches, macaws, raptors, and crows. It is a ritualized form of behavior that apparently bridges the gap between aggressive attacks and sexual behavior.

6. Why do large groups of blackbirds or American crows often attack a single hawk?

A: Mobbing behavior by crows is very common. The crows are reacting to the potential threat the hawk poses as a predator, to the adult crows and their offspring. The mobbing often serves to harass the hawk into leaving the area. Occasionally a mobbed hawk will turn the tables and attack and kill a crow.

7. How can I stop a woodpecker from pecking holes in my stucco house?

A: A woodpecker drilling on your wooden house is only doing what comes naturally to it – drilling into wood in search of shelter or food. Most house-wrecking woodpeckers do their damage in the fall, which is when they begin making their winter roost holes. Try mounting a nest box with an approximately sized hole over the drilled area. Fill the house with wood chips, and you may divert the bird’s attention and gain a tenant.

Woodpeckers also use wood and sometimes metal parts of houses as drumming sites. They drill their bills against the surface in a rapid staccato beat. This drumming noise is a territorial announcement, and a method for attracting a mate. Drumming happens most regularly in the spring. There are several things you can try. One of them may work.

  1. Place some sheet metal or heavy aluminum foil over the area the bird is using.
  2. Hang some aluminum pie plates around the affected area. Make sure they move in the wind (to scare the bird).
  3. Place a rubber snake near the drilling area (to scare the bird away).
  4. Repeatedly scare the bird when it lands on your house.
  5. If nothing else works, call your local wildlife official who may come to your house to “remove” the offending bird.

For more information on woodpeckers, get a copy of Enjoying Woodpeckers More.

8. Do large groups of robins indicate that a flock is migrating South for the winter?

A: American robins are surprisingly hardy as long as they have access to their winter food sources: berries and fruits. They switch over in winter from their mostly insect-based summer diet. As such, robins are facultative migrants. This means that they will migrate only as far south as they need to or are forced to by bad weather or food shortages. During ice storms, when berries and fruit are covered in a thick coating of ice, many robins flock together and move south. In the same way, if a robin spends the winter in your region, it’s probably because there’s enough food to see it through.

The idea that robins are the true first sign of spring is somewhat mythical. In much of northern North America, a few robins overwinter, but they stick to the woods and thickets where they can find fruit and berries. Most backyard bird watchers do notice the robins’ return when these birds appear on lawns with the onset of warm weather, seeking their warm-weather food: earthworms, grubs, caterpillars, and other insects.

9. Do wrens eject young bluebirds from their houses?

A: The wrens you are seeing at your feeders are probably Carolina wrens. They can co-exist with bluebirds peacefully. The wrens that cause problems are house wrens, which migrate south for the winter and will return in April and May to set up territories. Place your bluebird houses in the middle of a large grassy area, such as a meadow or large lawn. Place your wren houses along the edge of the trees or woods. This will keep the house wrens and bluebirds from fighting over housing.

10.Do all birds mate for life?

A: No. Some species have unusually strong pair bonds between mated birds. These species include some eagles, cranes, swans, geese, and ravens. Being mated “for life” means, really, for as long as both birds are alive. When one of the pair dies, the other will take a new mate. Most North American bird species pair up primarily to reproduce, and go their separate ways soon after they have nested. In some species, such as the ruby-throated hummingbird, the pair bond is very brief. In the case of the rubythroats, the pair bond lasts only as long as courtship and copulation. The male has nothing to do with the incubation or raising of the young birds. For answers to the most commonly asked bird questions, get a copy of The Backyard Bird Watcher’s Answer Guide.

11. Do all birds migrate?

A: Not all bird species migrate, but most do. Migration is defined as the seasonal movement of birds, north in the spring from the wintering grounds, and southward in the fall from the breeding grounds. Among the birds that are resident, or do not migrate, are many grouse, ptarmigan, and quail species, many owl species, pileated, red-bellied, downy, and hairy woodpeckers, white-breasted nuthatch, Carolina wren, northern cardinal, wrentit, ring-necked pheasant, Townsend’s solitaire, common raven, gray jay, and northern mockingbird.

12. Why do pileated woodpeckers peck holes in house siding, and is there a practical way to discourage them?

A: House siding offers woodpeckers a sheltered cavity ideal for initiating courtship behavior or territorial defense (flickers are notorious for drumming on drainpipes and chimney flues at dawn). The birds frequently mistake the buzzing of electrical wires and appliances for a colony of wood-boring insects or ants – a major part of a pileated woodpecker’s diet.

Placing wire, foil, sheet metal, or fencing over pitted siding may discourage pileated woodpeckers from pecking holes. Some homeowners have successfully deterred them using owl decoys, rubber snakes, loud noises, motion detectors, or by simply spraying the birds with a hose. In extreme cases, wildlife officials will “remove” a problem bird at the homeowner’s request.

13. A wren in my backyard is killing bluebird and tree swallow nestlings. What can I do to help protect these birds?

A:
I recommend two strategies. First, move the tree swallow and bluebird boxes into an open clearing (near the center of your yard, for example). Next, place the wrens’ favorite shelter in edge habitat. A wren rarely ventures into open spaces to challenge other birds for housing, especially if adequate shelter is readily available in its preferred habitat.

14. Why does the Ovenbird sing in sudden bursts after nightfall?

A:
During spring and early summer, male ovenbirds frequently sing at night, sometimes while flying over the woodland canopy. This courtship/territorial behavior is common during the breeding season, when the male becomes hormone-driven.

Comments on this entry are closed.

  • Nancy

    A Carolina wren has a nest with 4 eggs in one of my plants on my patio. The plant/nest is on a movable plant shelf. It would normally be fine but my homeowners association is having our patios and buildings pressure washed over the next couple of weeks. I’m not sure how to deal with this. I could try moving the shelf gradually out away from the wall and corner and hopefully the cleaners could work around the shelf but it would still be upsetting for mom and possibly babies by that time. Anyone have any suggestions?

    • Hi Nancy,
      Ask your HOA and the pressure-washing company to hold off on doing your patio. You could cite the International Migratory Bird Treaty Act of 1918, which protects all native birds. If they are going to disturb the nest, they must request a permit from your state’s wildlife agency. Here’s a helpful link: http://www.sialis.org/mbta.htm. According to that federal law, it is illegal to remove or move active nests, even if they are in an inconvenient location. Period. Of course, be courteous and polite to all parties, but be insistent that they do not disturb the nest. Ask them if they can come back later in the summer. Good luck, to you and to the wrens!

      • Nancy

        They came yesterday to pressure wash so I checked with them to see what all they were doing. My neighbor and I moved the whole plant shelf off the patio about 15 ft under a tree. I covered it with some plastic so it wouldn’t get the spray and left it open where she goes in and out. Once they were finished, we moved it back to where it was on the patio. She was back on the nest this morning. Hopefully everything will be OK. Thanks for the response. I was more concerned about all of that happening after the babies hatched out.

  • Kim

    I am concerned about a robin who lives in a nest outside of my apartment building. She hatched 4 babies earlier this year, but I think her mate is dead. After building the nest, the male never came around again. She has now laid four new eggs, but that was almost 3 weeks ago and they have not hatched. I am worried that since her mate is dead, the eggs are not viable and will never hatch, yet she is sitting on them vigilantly. I was told that robins mate for life. If that is true, will she never have viable eggs again? If I remove the nest, which she has reused, would she find a new mate? She has become somewhat of a pet so I want to help her, but I don’t know how. What should I do, if anything?

    • Hi Kim,
      You are a kind person! Female robins incubate alone, with no help from the male. Incubation usually starts wholeheartedly after she has laid the second egg, but on occasion, she delays incubation. Hatching begins 12 days to two weeks after the last egg is laid (usually three or four eggs in the nest). While she is incubating, it is rare for the male to bring the female food! When weather is warm, she can be away from the nest foraging (and not incubating) 70 percent of the daylight hours. The male will resume childcare duties when the eggs hatch. He will bring food to the young, and then feed the fledglings. It is not surprising that the male has not helped with incubation, but it is surprising that incubation is taking more than two weeks. Robins do not mate for life, just for the breeding season, and even then, they are not necessarily faithful partners. It is very likely that not all the eggs “your” robin is incubating have the same father. This is quite common in the bird world. It is rare for birds to truly mate for life, and even those that do usually find a new mate upon the death of their spouse.
      You didn’t say where you live, but even in the deep South, robins only have two clutches per season, max. If this is her second brood, it is highly doubtful that she would renest even if you took away these eggs. It’s almost July, and that’s really too late for a robin to start a clutch. In fact, by the latter half of June, ovulation slows down in female robins, and in July, the gonads of both males and females became inactive—according to Birds of North America.
      If I were you, I’d just let her sit on those eggs for a while longer. Either those eggs will hatch (any day now) or she’ll realize that she’s wasting her time. Next summer, she’ll find a new partner—even if this year’s mate is still alive after all—and start all over again.

      • Kim

        I was relieved to see that two of her four eggs have hatched yesterday! She still has two eggs in the nest left, but I don’t know if they will hatch. Thank you for your help. I live in Indiana, by the way. I have never been able to observe a bird’s nest this closely so this has been absolutely fascinating. God bless, Kim Crouch

  • kendab

    I have what I believe is a Carolina Wren that sleeps on the outside of my patio umbrella. There is no nest. He/She just hangs on and sleeps. There has been a pair but it’s mostly alone. Is this normal? I keep hoping to see a mate and/or a nest in my hanging fern. Feel bad for the little thing

    • Hi Kendab,
      Bird nests are nurseries, not bedrooms. Unless there are eggs being incubated or nestlings being brooded, adult birds don’t generally sleep in nests. (Exception: on cold night, cavity-nesting birds might sleep in a nest box for shelter.) In general, birds sleep on safe roosts. I’ve known of Carolina wrens to spend the night (regularly) on window sills (as if they were peering in), on shelves in garages, and in other odd places, although the outside of a patio umbrella does seem particularly odd. Not all birds find a mate each year, or maybe “your” wren is a male, and his mate is incubating or brooding on the nest. Dawn Hewitt, Bird Watcher’s Digest

  • M Johnson

    I’ve been watching a woodpecker (I think it’s a downy) feeding another which seems slightly larger and very round. Do woodpeckers feed their pregnant mates?

  • Karen

    Earlier this spring I had 100’s of tree sparrows and goldfinches. The tree sparrows all left and the goldfinches stayed a fewore weeks and they all left. Can you tell me why this has happened and will they return?? I am in Nebraska. Thank you!!

    • Bird Watcher’s Digest

      The tree sparrows likely migrated to their northern breeding grounds for the summer; they should return to your area next fall. The goldfinches should be year-round residents in your area; they probably didn’t go too far. Sometimes they move around in flocks, looking for food. Chances are good that they will return to your yard sometime soon; keep an eye and ear out for them!

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