Baffling Bird Behavior — Your Questions Answered

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!

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.

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. 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.

House siding also 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).

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 of attracting a mate. Drumming happens most regularly in the spring. There are several things you can try. One of them may work.

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.

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 same-sized hole over the drilled area. Fill the house with wood chips, and you may divert the bird’s attention and gain a tenant.

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 source: fruit, especially berries. 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 forest 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 fruit still hanging on to trees and branches 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 freeze-dried fruit. 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 compete with bluebirds for nest boxes 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.

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, some (but not all) woodpeckers, white-breasted nuthatch, Carolina wren, northern cardinal, wrentit, ring-necked pheasant, Townsend’s solitaire, common raven, gray jay, and northern mockingbird, and many others.

12. 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.

13. 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.

33 thoughts on “Baffling Bird Behavior — Your Questions Answered”

  1. 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!!

    1. 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!

  2. 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?

  3. 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

    1. 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

  4. 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?

    1. 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.

      1. 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

  5. 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?

    1. 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!

      1. 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.

  6. Hi, I’ve got a Carolina wren that made a nest with 10 eggs on my front porch. It’s been over 4 weeks that the 10 have been in there with her sitting on them most of the time with no hatching. I haven’t seen the female since yesterday. Could the eggs be infertile & she finally gave up? Side note, she started nest in early June, (August 4th now) and in all this time I’ve never seen a male hanging around with her either. Is it safe for me to finally clear off box that she built her nest in? lol

    1. Hi Lisa, Clutch size for Carolina wren is usually four, and up to six, but ten? That’s crazy. Incubation is usually about 15 days, so four weeks with no hatching, that’s very strange, too. Only female Carolina wrens incubate, but her mate typically brings her food. And now that the female seems to have abandoned this very odd nest, I think it is OK for you to clean out the box. I hope she has better luck next year! Dawn Hewitt, Bird Watcher’s Digest

  7. Delores Phillips

    I started with 4 wren eggs now have two Chicks…one looks very lethargic. The other is energetic and loud. I noticed they started in one nesting area and now are completely separated within the same nest. There’s actually a wall of straw between the two. Why is this. Should I do something?

    1. Hi Delores, It sounds like one of the chicks is off to an unhealthy start, although “runts,” or eggs that hatch as much as 48 hours after the others, have been documented in Carolina wrens. (You didn’t say which wren species this is.) I would suggest letting nature take its course, allowing survival of the fittest. By separating the healthy from the unhealthy, perhaps the mother wren has that in mind. But who knows? Maybe the smaller one is a late bloomer, and will rally yet. I hope so. Regardless, nature knows best. Good luck to both chicks. Dawn Hewitt, Bird Watcher’s Digest

      1. Delores Phillips

        Im.pretty sure they are Carolina wrens. Unfortunately… something got them last night. Nature is cruel and I’m heartbroken. Thank you for your help. This is a cool Page

  8. Sharron Edwardsholt

    Cooper Hawk: I have noticed that every few days the female hawk spends time off the nest (eggs are there) and the male starts taking sticks to the nest – would this be a part of the continued courtship? or to maintain the nest?

    1. Hi Sharron, I’ve looked this up in Birds of North America Online, and haven’t found much. It says that male Coops do the majority of nest building, and that it usually takes place in 2 weeks or less. Then, males generally avoid the nest, or are nervous around it. It doesn’t say anything about the males bringing sticks to the nest, or the female spending large blocks of time away from it. “Most diurnal and all nocturnal incubation by female. Male may incubate 10–25 min, 2–3 times daily, arriving at nest only after female leaves to accept and consume delivered prey at nearby transfer perch; departs nest immediately as female returns ( Meng 1951 , RNR and JB). Attendance constant except when female leaves nest briefly (2–25 min) for prey deliveries, vocal exchanges with male at dawn, defecation, and chases of predators, or when female stands to preen on nest. One female incubated 84% of daylight hours ( Meng 1951 ).” That’s copy and paste from Birds of North America Online. So, I’m afraid I don’t have an answer as to why the male would continue to bring sticks to the next while there are eggs there. I’m sorry I don’t know! Enjoy this great show! Dawn Hewitt, Bird Watcher’s Digest

      1. Sharron Edwardsholt

        Thank you so much for the reply. I find bird books great on preat on identifcation but scant on behaviour. Thank you again.

  9. MaryLynn Gillaspie

    We witnessed a pair of crows building a nest across the street. Wasn’t sure if they’d laid eggs yet, but then saw a hawk in the nest, with crows yelling at it… Since then, I’ve seen them in the nest just a couple of times over the past few days – certainly not with the regularity they had been there. I am wondering if the male might try to coax a different female there? Why would they return occasionally?

    1. Hi MaryLynn, I assume the crows across your street are American crows. That species has just one nest per year, but if the first clutch fails early in the breeding season, it will try again. I suspect it is the same male and female crow returning to the nest, trying to decide whether they should renest there, or elsewhere, or at all. Crows are presumed to have long-term pair bonds, so it is doubtful that the couple “divorced” after the hawk interfered with their first nest effort.
      Dawn Hewitt, Bird Watcher’s Digest

    1. Is your wren a house wren? Male house wrens fill several cavities with sticks, and the female picks her favorite to nest. Perhaps you watched a male prepare a potential nest box, but the female chose a different one? I really can’t offer a better guess without knowing whether the wren is a house or Carolina or Bewick’s or some other wren species. Are there eggs in the nest? Or young? I need more information to provide a better answer. Dawn Hewitt, Bird Watcher’s Digest

        1. Thanks for the photos, Victoria. It’s not a house wren. With those eye lines, I’m guessing Carolina or Bewick’s, and the eggs look right for either. So, are the eggs still in the nest? If not, it’s likely that a snake or other predator got them, and the parents abandoned the nest. Only the female incubates, so if she died, the male will abandon the nest. If the eggs have been in there for six days (and cool nights) without incubation, they are no longer viable. It’s sad! Dawn Hewitt, Bird Watcher’s Digest

  10. For the last five days a robin has continuously thrown itself against the front window of my house. I pull the shade down bang on the window and it waits until the next morning to continue this bizarre behavior. Today it started at the same window until I scared it off, so it went to the side window where it has continued throwing itself against this window for several hours. What the heck is going on?

    1. This is one of the most common questions we get here at Bird Watcher’s Digest, and the solution is relatively easy, if not exactly attractive. Your house is in or next to a robin’s nesting territory, and sees its reflection as an intruder. It is trying to threaten or fight off what it sees as another male robin on his turf. This behavior will continue throughout breeding season, which, depending upon where you live, could be a few months. So, get some newspaper or open up brown paper bags, and tape them to the outside of the windows the robin attacks. Leave the paper in place at least a week, or longer if you have to. You need to change the reflectivity of the outside of the window. Once the bird has a nest full of eggs or young, it will probably be too busy tending them, and won’t feel threatened by an interloper. It might not even have time to check your windows to see if that intruder is back! But if you live in a place where robins produce multiple clutches during a summer, it could start up again as he and his mate start thinking about another brood.
      Good luck to you and to your robins! Dawn Hewitt, Bird Watcher’s Digest

      1. I live in Rhode Island. What can I expect the rest of the spring and summer? How large might this “nesting territory” be? Thanks for your reply and knowledge.

        1. I’m excerpting from Birds of North America Online. Robins regularly produce two broods per summer, three if one nest fails. In New England, robins have young in the nest for a total of about 60 days, with the peak of egg-laying being May and June. The size of its territory depends upon the population density of robins in your area. The size can be from 1/10 acre to more than two acres! Try hanging paper for a week. Take it down from one window, and see if the robin returns. If not, you’re good. If he does return, hang it again for another week. He might just have to unlearn his habit of expecting that same old intruder every day. Please understand: I’m no robin expert, but I do have a lot of resources at my disposal! –Dawn

  11. Hello, i have tried to change things around t in a vain attempt to find a possible answer myself, but.. i am truly baffled! Maybe you can shed some light on this strange behavior. I will make this as easy to read as possible so as not to bore you, and to keep your mind working in order to see if anyone can work this out?
    1. bird table, approx 6 feet from the hedge row, lots of trees behind, plenty of cover, away from any roads, overhead cables etc etc, 3 bird feeders 1 nuts, 1 seeds, and 1 fat balls
    crows, rooks, pigeons, bit tits, little tits, finche’s woodpeckers (both spotted and green) robins, you name it, they all turn up, even pheasants, all the food is eaten, water is also changed or topped up in the bird bath a few feet from the ‘table’. are you with me so far? simple enough.
    Some time later we purchased a 2nd bird table, (2+ years ago) different in design, and with a nesting box in the top of the roof area, where some time ago some tits entered and raised their young successfully! BUT! along with the nuts cage, seeds cage and the fat balls cage, the nuts were not being touched bear in mind the nest has been ‘flown’ for over 2 years now, this 2nd table is approx the same distance from the hedgerow and trees as the other one but these are about 15 feet apart from each other. i noticed that the nuts (looking from the kitchen window) on the 1st original table were being eaten and having to be topped up every 3 days, the 2nd one (over on the right) was not being touched??? both nut cages are exactly the same. later i repaired one of the tables bottom section and re-varnished the new parts fitted, at first i thought maybe the smell/aroma had affected the ‘air’ in some way, but they were not really eating from the table on the right (table no.2) in the 1st place?
    so! what do you do? i simply swapped the tables over and didn’t move the nut cages over, but continued to top up the favoured one and waited….
    sure enough, all the nuts went in 3 days???? the one now at no 1’s position was having the seeds eaten and the fat balls, but the nuts were being left????
    so! next up i decided to let the nuts that were being devoured empty, i did so for over a week…… the other nuts were untouched! the seeds were being eaten on both tables, all the birds were still coming to the tables, but the nuts were not being eaten, so! to keep you all interested i have done absolutely everything, i have swapped the nut cages over, i have filled both just to find the same cage is left full, and if the favoured one is empty, the seeds are taken and no nuts, the birds will even fly past the strange cage full of nuts to the other table and take what ever is left in the favoured one! there have been about 4 nuts left, yet still they fly past the dull cage on the left and take what is in the no. 2 cage???? so! after doing virtually everything possible (believe me i really have!) even repaired the other base with new wood so i know this has nothing to do with it, the distance, wind direction, time of day, type of birds etc etc has nothing to do with it, so as a last resort (it’s ok, the end is coming!)
    where the ‘undesirable’ nut cage had been ‘picked’ a couple of times in the month since i filled it, i have poured in a stack of bird seed in a vain attempt to entice more feeding, and filled the desired cage to the brim, i done this 4 days ago, now i know some of you will say ‘ but the seeds will fall out through the larger holes of the nut cage’….. well folks, the stack (about 3 inches deep!) is still there!!! untouched! yet the cage now in position 1 which i removed from table 2 and remains the desired cage has been empty for 2 days!
    so! i have moved, swapped, changed, re-filled, tried to entice, repaired both, re-varnished both and yet both cages are the same size shape and make, yet still these crazy birds choose to leave nuts off their list boycott the full cage and wait for the re-fill (in between eating seeds from BOTH tables!!!!
    MY head hurts now!

  12. Deborah Beckwith Rodriguez

    We have a solitary Black Phoebe who hangs out in our yard. We have discovered that he (maybe she) gets into our roofed and curtained cabana each night. And he’s pretty clever to get in there, swooping up under the overhang and onto the curtain rod and into the structure – it’s not a wide opening. Is it typical for this bird (or any bird) to take shelter like this at night? We gave him quite a surprise last night when we opened the curtain. While messy for us, we are fine him staying…….we’ve just never had this happen before and wonder why this bird feels the need to have his own bedroom.

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