ask the lab

Each month, we’ll post a new set of Q&A and add to the archives. You can search topics with the “Search” tool on every page.

GOT A QUESTION? Click here to ASK THE LAB or email us at askthelab@wildbirdclub.com



Q. A birding friend keeps using the word “Zugunruhe.” What is that??

A. Every year in spring and fall, wild birds, and many in captivity, suddenly start acting different. They often increase their eating, putting on weight. They also start acting more restless. Scientists have kept migratory songbirds such as Indigo Buntings in special cages that show the birds’ nighttime activity patterns. Most of the year the birds spend the night sleeping. But in spring and fall, they spend part of the night trying to move. In spring, their movement patterns show they’re trying to head north, and in autumn, south. This unusual migratory restlessness pattern was first noticed by German animal behaviorists who named the restless condition Zugunruhe (Zug  means to move or migration, and Unruhe means anxiety or restlessness.)


Q. A robin keeps flying into my window. Why?

A. Robins, cardinals, and a few other species are so territorial that if they spot a potential intruder on their “property,” they may spend days trying to drive it off. In nature, when a robin or cardinal sneaks onto another’s territory, it usually flies away when the territory holder raises its crest and makes warning calls, and virtually always flies away if the territory holder actually chases it. So it mystifies and upsets a robin or cardinal when that “bird” in the window stands its ground and just won’t leave. The fact that the reflected bird doesn’t sing a territorial song makes the situation for the real bird even more confusing, and it may get fixated on trying to drive the upsetting image away. Covering the window for a few days usually resolves the situation.


Q. Are geese the only birds that fly in a V? How high to migrating birds fly??

A. No. Many large birds form a V when flying in groups. Cranes, pelicans, ibises, and even gulls often take a V formation while flying in groups.

The altitude of each migrating bird depends upon its species, the weather, the time of day or year, and geographical features on the ground below. Nocturnal migrants often take off shortly after sundown and rapidly gain maximum altitude where they remain until about midnight. After that, the birds slowly descend until daylight. Most songbirds fly between 500 and 1,000 feet, but some small nocturnal migrants (probably shorebirds) fly over the ocean at 15,000 or even 20,000 feet. And yet other shorebirds, sea ducks, and songbirds may fly along shorelines so low that they barely stay above the waves.


Birds such as raptors and cranes can fly at very high heights in the daytime, when they can capitalize on thermal air currents on sunny, low-wind days to carry them upward. Cranes have been recorded up to 15,000 feet.  And some shorebirds can fly incredibly high, like at 20,000 feet, at nighttime.


Birds can fly much higher than bats, because birds have such efficient respiratory systems. Birds have no trouble at high altitudes, where there is much less oxygen than lower, while mammal lungs are not as efficient. Bats have been recorded at 10,000 feet, but usually fly between 600 and 3,200 feet.



Q. Why are chickadees singing when it’s so cold outside?

A. Black-capped Chickadees make their chickadee-dee-dee call notes year round to communicate with one another. Their “spring song,” the clear, whistled Hey, sweetie, helps males attract a mate and claim and defend a nesting territory; they begin singing fairly regularly in January. They won’t start nesting until April at the earliest, but sing quite a bit during the coldest part of winter, when pairs form within winter feeding flocks. As days grow longer, these pairs may separate from the flock on mild days to start inspecting possible sites for nesting territories; their singing will increase as they do this. As warming temperatures allow them to spend even more time on their territories rather than with the feeding flock, they’ll sing more and more. But by then, robins and other birds will be singing, too, and the chickadee songs won’t stand out quite as much, or be as welcome as they are during the frozen months.

You can hear chickadee sounds here.




Q. Are there any birds that nest in winter?

A. Birds can only nest when they can keep their chicks safe (including warm enough) and there is abundant food. Most species wouldn’t even consider nesting in northern states in winter. But some actually do start nesting even when temperatures can be below zero! Great Horned Owls usually start laying eggs by late February. The large female stays on the eggs while the male hunts to provide food for her as well as himself. The eggs won’t hatch until March or April, but even then it can be cold, so the male continues hunting for his family while the female sits tight keeping them warm.


Crossbills, winter finches that specialize on cone seeds, also can nest in the dead of winter in years when cones are abundant. The male and female take turns keeping the eggs and chicks warm while the other flies off to feed. Crossbills, like most finches, feed their young regurgitated seeds, so a large meal for a parent provides food for the young as well.


January isn’t very wintry in many areas. By the end of the month, many non-migratory birds will be starting their nesting behaviors in Florida. And albatrosses such as the famous Laysan Albatross named Wisdom have been sitting on eggs on Pacific islands since December.



Q. How do I get better at counting birds?

A. If you have a digital camera, try making quick counts or estimates of wild birds and take a photo to count them at leisure, to compare what the real number is with your field count. Practice counting flocks with other birding friends, too, to compare your counts. If you get into the habit of always counting birds, even in very small flocks, little by little that constant practice will help.



Q. I just bought a new field guide, and thought it was supposed to keep related birds near each other, but the Northern Cardinal and Rose-breasted Grosbeak are separated by a lot of pages from the Pine and Evening Grosbeaks. Why?

A. These two groups of birds are indeed similar looking thanks to that oversized beak. And for over a century, American scientists thought they were closely related. But we now know from DNA analysis that the two groups are not at all closely related. Those large beaks turn out to be a wonderful example of convergent evolution. The birds have similar diets, and so they’ve independently evolved that oversized “gross beak” to help them crack seeds with hard shells.



Q. Is it true that adult loons and hummingbird migrate before their chicks? If so, how do the young find their way?

A. Yes, it’s true that adult loons and hummingbirds both head south days or even weeks before the young leave. Young loons take a long time to be able to fly, until long flight feathers are all grown in. But in late summer and early fall, there can be fish die-offs or some lakes can be depleted of fish simply because loons eat so many. If the adult loons head out as soon as their chicks are doing well catching their own food, what food remains can all go to the chicks rather than be shared with the adults. Young loons have a strong urge to fly, so as soon as their wings can support them, off they’ll go! And they have an innate urge to head south in fall, so they’ll head in the right direction.

The situation is similar for hummers. Droughts and early frosts can deplete flowers of nectar. When adult hummingbirds head out, what remains can go entirely to the young of the year. Again, hummingbirds have an innate urge to migrate south in fall, so they, too, have no problems finding their way, and know that they need to head out as soon as their body feels ready—which it will when their muscles and fat are at the proper levels for migration.



Q. Why do some birds fly in flocks while others don’t?

A. There are great advantages to associating with a flock during migration. With more alert eyes searching for danger and calling out warnings, there’s a greater chance of eluding predators. Rich food sources are more likely to be discovered when there are more eyes searching. And birds with exhausting flapping flight conserve energy when flying behind another bird.

Flocking birds often feed in large groups at rich food supplies. Waxwings and robins eat mostly fruit in winter. When one of the flock detects, say, a crabapple tree laden with fruit, the entire flock can pig out, moving on when they deplete the tree. A large farm field may provide plenty of food for even a large flock of blackbirds or cranes.

But many food items are harder to find, and not distributed in such large quantities. When a hummingbird discovers a small stand of nectar-rich flowers, it must fight off competitors or risk not having enough food for its own needs. This is why hummingbirds don’t migrate in flocks.

Raptors take advantage of thermals to rise in the air—then they can glide forward, losing altitude, until they detect another thermal. They can find these thermals by feeling the rush of rising air, but will find many, many more by watching for other birds rising on thermals. Sometimes hundreds of hawks may be spiraling up on the same rising column of air at the same time. These birds aren’t really associating with one another, but simply paying attention to where thermals might be. At the end of the day when the birds stop migrating, they tend to separate, each going its own way to find its own food for the night. Because these migrating hawks don’t form any bonds or stay together except when gathered on a good thermal, these groups aren’t called flocks. Instead, because so many birds rising on air at once reminded someone of steam coming out of a tea kettle, these collections of hawks are called kettles.



Q. What are some easy ways to observe birds in August when they’re so quiet and secretive?

A. There are more birds in July and August than any other time of year because of all the baby birds. But the young birds have to be fairly quiet to stay safe from predators, and adults, molting into new feathers, also grow quite secretive. But pay attention and you may notice quiet little whispery or squeaky calls by the young birds begging for food. Bird families usually stay within foliage, but if you watch quietly for movement, you may see lots of interesting activities.

Even easier, set up some sort of hide or photographic blind near a bird bath. A small tent works wonderfully. Here is where quiet patience can be richly rewarded!



Q. Cowbirds are always raised by other species. How do they learn that they are actually cowbirds?

A. When a baby duck or goose is raised by a human from the time it hatches, that little bird imprints on our species and never realizes it’s really a duck or goose! But baby cowbirds never imprint on the bird raising them. How do they know to flock with other cowbirds instead of sticking with sparrows, warblers, or other foster parents?

Recent field research by Mark Hauber at the University of California, Berkeley’s Museum of Vertebrate Zoology is shedding some light on this. Cowbird adults make frequent visits to nests with cowbirds, and even a six-day-old, still blind nestling cowbird will respond to their calls in much different ways than it responds to any other sounds. The cowbird chatter call apparently works as a “password” that birds must hear and learn to realize they’re cowbirds. If a cowbird is raised in captivity with canaries and never exposed to other cowbirds through its first winter, it will think it’s a canary and only associate with them. Hauber believes that the cowbird’s begging calls are similar to this chattering “password” helping draw other cowbirds to it when it leaves its foster parents.

Throughout the time young cowbirds remain with their foster parents, adult cowbirds keep visiting them (perhaps drawn by the young cowbirds’ begging call “passwords”) and teach them important cowbird behaviors. Only two weeks after hatching, young cowbirds leave their foster family to join flocks with their own species, where they learn more cowbird-specific skills. If they know the secret password, their life as a cowbird is ensured.



Q. Why do mockingbirds and thrashers mimic other species?

A. Scientists used to think that by mimicking other birds, these mimics could banish other species from their territory, perhaps so they wouldn’t have to share food resources. But now they think it has much more to do with impressing females, because the more different sounds a male includes in his repertoire, the more he succeeds in attracting a mate. These sounds each represent experiences the male has survived, so the more sounds in his song, the older and more experienced he is.  



Q. Why do a few birds, like Red-eyed Vireos, sing all day long while others limit their song to the morning?

A. Every species has specific approaches to the issues surrounding survival and raising young. In species in which both the male and the female feed the young, they both need ways of figuring out how healthy and reliable potential mates will be. In Red-eyed Vireos, females can judge males by how persistently they sing. And steady singing also signals nearby males that this singer’s territory has a strong male defending it. Each song is brief, and the males can search for food and go about most of their other daily activities as they sing, so this system works well for them.



Q. Lewis and Clark were the first European Americans to see many Western birds. Why were only two, Lewis’s Woodpecker and Clark’s Nutcracker, named for them?

A. Most birds that are named for a person were named in honor of the first person to send a bird to a museum and to properly describe it for the scientific literature. The problem for Lewis and Clark, who brought back a great many museum specimens, was that when they returned, Meriwether Lewis was suffering from crippling depression, and between the two explorers, he was the naturalist charged with collecting and writing about the animals and plants they encountered. Many other explorers brought back birds from the West and published their findings before Lewis got around to writing up his own sightings.




Q. Why do Sandhill Cranes gather on the Platte River, and how long do they stay there?

A. A long section of the Platte River, roughly from Grand Island to Kearney, is a staging area for cranes as they migrate north in spring. The cranes that gather in Nebraska are headed for Alaska, and some even to eastern Siberia! Before making the long final leg of their journey, they fatten up along the fields near the river, and all gather in the shallow water at nighttime—the safest place to avoid predation. Each pair of cranes remains in Nebraska for roughly a month. They first start arriving in mid-February, and migration lasts through early April; the peak is in the last two weeks of March.




Q. Why are chickadees singing when it’s so cold outside?


Black-capped Chickadees make their chickadee-dee-dee call notes year round to communicate with one another. Their “spring song,” the clear, whistled Hey, sweetie, helps males attract a mate and claim and defend a nesting territory; they begin singing fairly regularly in January. They won’t start nesting until April at the earliest, but sing quite a bit during the coldest part of winter, when pairs form within winter feeding flocks. As days grow longer, these pairs may separate from the flock on mild days to start inspecting possible sites for nesting territories; their singing will increase as they do this. As warming temperatures allow them to spend even more time on their territories rather than with the feeding flock, they’ll sing more and more. But by then, robins and other birds will be singing, too, and the chickadee songs won’t stand out quite as much, or be as welcome as they are during the frozen months.


You can hear chickadee sounds here: https://www.allaboutbirds.org/guide/Black-capped_Chickadee/sounds 




Q. Are there any birds that nest in winter?

A. Birds can only nest when they can keep their chicks safe (including warm enough) and there is abundant food. Most species wouldn’t even consider nesting in winter! But some actually do start nesting even when temperatures can be below zero! Great Horned Owls usually start laying eggs by late February. The large female stays on the eggs while the male hunts to provide food for her as well as himself. The eggs won’t hatch until March or April, but even then it can be cold, so the male continues hunting for his family while the female sits tight keeping them warm.

Crossbills, winter finches that specialize on cone seeds, also can nest in the dead of winter in years when cones are abundant. The male and female take turns keeping the eggs and chicks warm while the other flies off to feed. Crossbills, like most finches, feed their young regurgitated seeds, so a large meal for a parent provides food for the young as well.




Q. What’s the difference between the Christmas Bird Count and the Great Backyard Bird Count?

A. The Christmas Bird Count, started by Frank Chapman of New York in December 1900, quickly became an annual ritual organized by Audubon. It’s provided a wealth of data about birds in early winter. It follows a specific protocol, with birds counted within “count circles” 15 miles in diameter. Each circle’s count is coordinated by someone to ensure that the circle is as thoroughly covered as possible and that birds aren’t double-counted. Each circle’s count falls on a single day between December 14 and January 5. Most participants devote the entire day to the count.


The Great Backyard Bird Count was started by the Cornell Lab of Ornithology in 1998; it happens each year during the second week of February, after northern visitors have arrived in the US and southern Canada in large numbers, and after late fall stragglers have disappeared. Anyone can participate wherever they want to count birds, including their own backyards or favorite birding locations. Each participant’s count is sent directly to Cornell rather than to a local count coordinator. Participants are welcome to devote as much or as little time on their count as they choose.


Both counts are essential tools in figuring out bird populations in winter. Their protocols are entirely different, and so the numbers aren’t directly comparable, but each provides an important snapshot of bird populations at a particular point in winter. Both are fun and valuable.




Q. Why do birds look so much bigger and plumper in winter?

A. Before winter starts, many birds pig out as much as possible to have extra body fat. On days when the weather is too horrible to spend much time out in the open, they’ll have some fat to burn to stay alive. But even with extra fat, they look pretty much the same size under their feathers. So what makes them LOOK fatter? Those feathers! Every bird feather is attached to a tiny muscle. A bird can control each muscle to make a feather lie flat or stick up. In winter, they erect the tiny downy feathers that are hidden below their outer feathers, so there is a large layer of soft down and air between the bird’s actual body and the outer feathers that we see. This thick layer insulates the bird to keep it warm. If you had a tiny thermometer and took a chickadee’s temperature in winter, it would be about 104–108 degrees Fahrenheit, just millimeters from where the air might be below zero!




Q. How can birds that feed on insects migrate through cold areas in late fall or even stay all winter?

A. Birds that need flying insects or glean for insects from leaves must migrate fairly early in fall. But those that are good at finding insect eggs or pupae can continue to find them in winter, in tiny crevices in tree bark, in the round, hard “galls” in goldenrod and other weeds, and in other places they figure out when weather is warmer. Most of the birds that eat insects in winter, such as chickadees, can supplement that diet with other things. Suet is a favorite for woodpeckers, chickadees, titmice, and other insectivores. Many can also digest some seeds.




Q. At places like Corpus Christi, Texas and Hawk Mountain, in Pennsylvania, people say they’ve seen tens of thousands, or even a hundred thousand birds in a single day. How can they possibly count them all?

A. When hawks are in a large swirling mass called a kettle, it’s impossible to count them all! But within that kettle, each hawk is spiraling upward. When it reaches the point where the air current is no longer strong enough to push it upward, it pulls its wings back and glides forward in the direction it’s migrating. Hawks reaching the top are all headed in the same direction, and are easier to count in the line or stream of birds moving forward. Hawk counter assistants keep track of where these hawks stream to, because they often form a new kettle and the counters don’t want to count the same birds twice!



Q. Summer is when more birds are alive than any other season. So why are they so hard to find?

A. Most male birds stop singing after they no longer need to defend their territory and attract a mate. Parent birds attending to young usually make sounds only to warn others of danger, and most nestlings and fledglings make only very soft calls so they won’t attract predators. More and more ripening berries and the insects they attract provide rich food sources, but most birds stay hidden inside the branches, or work the outside branches very quietly.

So how can you see them? When you walk through the woods, pay attention to the smallest movements and softest sounds. You may not see many birds, but as you learn to observe these subtle signals, you’ll see some of the most exciting behaviors, such as fledglings begging and adults feeding them.

One secret of quality summer birding is to set up a birdbath in a quiet, shady area of your backyard near a safe retreat such as shrubs. Hide in a little tent to observe the birds that visit close up.



Q. Some birds imprint on their parents while others don’t. Why?

A. Birds that are helpless when they hatch can’t control who comes to the nest to feed them—they simply open their mouths when anything jostles the nest. Birds that leave the nest immediately after hatching, such as ducklings, must be able to identify their mother to follow her very quickly.



Q. Why do loons and hummingbirds abandon their young before migration?

A. The young of these species take a lot of time before they’re ready to fly long distances, but as summer ebbs, their supply of fish or flower nectar can dwindle. By leaving as soon as the young can feed and protect themselves, the parents insure that there will be enough food to get their offspring ready to leave.



Q. How can birds raise young on the tundra?

A. Those that nest directly on the ground must line their nests with something that protects the eggs and chicks from cold. Ducks, geese, and swans create a thick lining of down feathers plucked from the mother’s own belly. Tundra weather seldom gets hot, but during the brief summer there are so many insects and so many hours of sunlight per day that birds can feed their young much more often per day, making the nesting season much quicker.



Q. I thought I knew my bird songs, but I just learned that a lot of species have two different songs. Why?

A. Bird songs usually serve two different functions: to attract a mate and declare and defend a territory. Some birds use two different songs, each serving one of these purposes.  It makes learning the songs twice as hard, but when you learn the different sounds, you can more easily figure out what the birds are doing.



Q. I’m learning about warblers, and how they each have a special habitat. But the ones I’m seeing are all flocking together, and not at all in the right habitats. Why?

A. Most warblers are extremely specialized, nesting in or under specific types of trees and feeding on insects in particular areas of the trees, depending on which warbler species. But to get from the tropics to their northern breeding ground, they must pass through a lot of inappropriate habitat. For example, virtually every warbler must fly over Interstate 80. To make this long journey as safe as possible, they flock together, searching out food and watching for predators together.



Q. My children and I have just started identifying the birds in our yard. Should we be submitting our data to the Great Backyard Bird Count?

A. Your data about the birds you do recognize is very important! On our website (http://gbbc.birdcount.org/) you can get tips on how to ID tricky species. See Learn About Birds.



Q. One night the temperature here in northern Minnesota got down to 30 below and our window cracked. But first thing in the morning, our chickadees and other feeder birds were there, just as abundant as the day before. How did they survive?

A. During the most frigid nights, some birds such as bluebirds, Tree Swallows, and Brown Creepers, may crowd together in a tree cavity or nest box, their bodies keeping one another warm. Others fluff up their down feathers to be as well-insulated as possible, and shiver whenever their body temperature starts to drop. As long as birds have enough body fat that they can “burn” overnight to shiver, they can survive. To help, chickadees allow their body temperature to drop on cold nights. That saves energy just as when we turn down our house’s thermostat overnight, we save energy.


Q. What are the best foods for winter birds?

Foods with the highest fat content are extremely valuable on the coldest days. Black oil sunflower is better than striped sunflower both because it has more fat and because the shells are thinner, so the birds don’t have to use as much energy to open the seeds. Suet is extremely valuable for a good variety of birds. Bread, donuts, and other high-carb people food are never nutritious for most birds, and attract mice and rats.


Q. My friend has a pet parrot and gives him grit. She says I should be giving the birds in my yard grit. Is that true?

Birds don’t have teeth, so the ones that swallow whole seeds must have grit in their gizzard (the muscular part of their stomach) to grind down the shells. And even shelled seeds can be hard to digest without grinding them down. So virtually all seed-eating birds eat some tiny stones or other gritty material. A side benefit of grit is that seeds lack many minerals, and many kinds of sand and pebbles have calcium and other minerals that are released as the grit wears down in the gizzard.


You can use pet store grit, beach sand, sand from a child’s sandbox, or crushed eggshells. Offer the grit in a special spot on the ground or on a platform feeder.



Q. What are the food and feeder preferences of common feeder birds?

A.  We’ve put together a list of almost 100 common feeder birds and cross referenced what they like to eat and where they like to eat it. Explore your region to see what you might be able to attract to your feeder this winter! Explore now!



Q. Is it okay to feed birds pumpkin seeds?

A.  Pumpkin seeds are nutritious food for birds. They can eat raw seeds, but wet seeds, especially when soaked with pumpkin pulp, get moldy quickly, so it’s safest to bake the seeds first. (See directions in this month’s intermediate activity)



Q. I don’t have any birds at my feeder. Are they disappearing?

A.  In November, a great many migrants from the north have already passed through the northern and even central states, but many of the winter visitors from the far north haven’t arrived yet. Meanwhile, our area residents, including the birds that are counting on your backyard for an important food source, often spend nicer days eating natural food that is still available. They also scout about looking for other sources of food that they can turn to during the worst of winter if your feeders stop providing food. So November is often a month when our feeders have very few birds.



Q. Do hawks spit out pellets like owls do?

A.  Hawks have far more acidic stomach juices than owls do, which helps hawks break down and absorb some of the calcium in bones and some other material in their prey that owl stomachs can’t digest. Also, hawk beaks jut out farther from their facial feathers than owl beaks, allowing hawks to pull out the muscle and organs, which are easily digested, leaving some of the bones and fur behind. Owls are more likely to swallow their prey whole. Hawks do spit out pellets that include the parts of their prey that they swallowed but can’t digest, but their pellets don’t contain all the bones and fur of every prey animal as owls do.



Q. Why are so many songbirds found dead in big cities on fall mornings?

A.  Many of the songbirds that winter in the tropics migrate by night, when air temperatures are cooler, winds are usually lower, and bird-hunting hawks are asleep. During foggy or drizzly conditions, they get bewildered by city lights, especially on tall, lighted buildings. When they take off from a tree at night, they instinctively know they have a safe path through the twigs and branches if they fly directly toward a light, which would in their natural setting be the moon or stars. When they’re disoriented by fog, they probably follow this same instinct, but in cities the lights they see make them collide with buildings.



Q. Is it true that birds crash into lighted buildings and towers? Why can’t they see them?

A.  Birds that migrate by night do indeed crash into lighted buildings, towers, lighthouses, etc. No one knows the exact reasons for this, but some people speculate that when birds first take off at night from a tree, they know they won’t crash into branches if they have a clear path toward the moon or stars. If they are lost in fog or low clouds and suddenly spy a light, they head directly for it.



Q. Someone said there are more birds in fall than any other time of year. Is that true?

A.  The time of year with the fewest birds is the end of winter, after all the losses of birds to migration and bad weather. Some birds start breeding in early spring, and throughout spring and early summer, they’re producing more and more young. Once migration starts, birds can be killed but are no longer replenishing their numbers by nesting, so the highest number of birds is probably right before many birds start migrating away from their breeding grounds.



Q. I found a baby bird! What should I do?

A.  If you find a baby bird that is a helpless nestling, try to return it to its nest. If it is hopping about on the ground, its parents are almost definitely nearby. Baby birds need much more than food to thrive, and people, including licensed rehabbers, can’t give them all the benefits their wild parents would. Wildlife rehabilitators try to restore baby birds to their own nest or the nest of another bird family of the exact same species with young at the same state.

This web page may help you find the nearest licensed rehabber: www.nwrawildlife.org



Q. Birds were singing so much in spring. Why do they quiet down so much in summer?

A.  In spring, most bird song is to help males defend a territory and attract a mate. By summer, these jobs are done and now most male songbirds are working with their mate to raise the young. At this point, the quieter they are, the less likely it will be that predators find their young.



Q. A robin has been singing starting at about 4 am every morning, on the roof ledge right outside my window! I love robins, but this one is driving me bonkers. What can I do?

A.  To get the robin to sing his dawn song from a perch further from your window, try setting out a few helium balloons to sway in the wind near his rooftop perch. Many birds are terrified of the unpredictable movements of balloons. He almost definitely won’t abandon his territory—just that particular perch.



Q. Should I be feeding birds in summer?

A.  Summer feeding can be fun for you and healthy for the birds as long as you follow a few rules.

  1. Don’t offer suet or peanut butter when it’s warm—they will get soft and goopy, making bird feathers greasy or even damaging them, and spoiled suet can be dangerous.
  2. Don’t leave out jelly if parent birds are feeding it to their nestlings or new fledglings. It’s higher in carbs than most of the natural foods birds feed their young. As young birds grow, they need a diet fairly high in protein.
  3. Don’t let seeds and other food items get wet. Moldy seeds are dangerous for birds.



Q. A family of wrens nested in my yard, and I watched both parents feeding the babies for two weeks. Then suddenly one day the whole family was gone. What kind of predator would have taken them all?

A.  When most birds fledge, they don’t return to the nest again. Baby birds have hot bodies, and the warm moisture inside a nest box can foster lice, mites, and other parasites. So as soon as the young are ready, they leave the nest, often all during the same morning, and they never return. House Wren young are in the nest just 15–17 days before fledging, so your birds almost certainly fledged safely.



Q. One of my friends keeps peeking into the House Wren nest in her yard. Shouldn’t we leave them alone during this vulnerable time?

A.  Checking nests, also called monitoring them, can be done very safely if you follow a few precautions:

  1. Peek in no more than once a day. It’s best to check only once every 3-4 days;
  2. Wait to peek in until you’ve observed the attending parent fly off;
  3. Approach and leave the nest in different directions to minimize the chances of predators discovering the nest;

To avoid the risk of young fledging prematurely, don’t check the nest again after the nestlings are well feathered or if they crouch when they notice you.



Q. How often should I change my sugar water?

A.  Even when we start out with boiling water and clean sugar, bacteria start growing in sugar water as soon as we set our feeders out. The warmer it is outside, the faster the bacteria grow. So during hot weather, it’s best to change hummingbird water every two or three days, and sooner if you see any cloudiness in the water. The water can be out a day or two longer when it’s cooler outside.



Q. I always see my first hummingbirds before wildflowers. What are they eating?

A. When hummingbirds first arrive in an area during migration, they are often drawn to the tiny holes sapsuckers drill in trees. They eat the sap and any bugs attracted to it. They also feed on tiny drips of sap on the tips of buds and leaves. And they are great at finding the first insects flying about.



Q. How often should I clean my hummingbird feeders, and is it okay to wash them in soap or detergent?

A. It’s extremely important to keep hummingbird feeders clean and the sugar water fresh. Every time you replace the sugar water, rinsing your feeders with very hot water and swiping with a bottlebrush is sufficient for regular maintenance, unless the water is growing cloudy or black crud is developing in crevices.

To give feeders a more thorough cleaning, and for regular monthly maintenance, soak them in full strength white vinegar. After a long soak and thorough brushing, rinse thoroughly and allow the feeders to air dry completely before refilling.



Q. One of my field guides doesn’t have our common backyard oriole, the Baltimore Oriole, but it shows a bird that looks like it called the Northern Oriole. Is that just a different name for the same bird?

A. Almost. Early British colonists started calling this bird, bright orange like the colors marking Lord Baltimore’s family crest, the Baltimore Bird or Baltimore Oriole starting in the 1600s. When the American Ornithologists’ Union standardized common names for the first edition of their checklist in 1886, they stayed with tradition and officially called it the Baltimore Oriole, a name that lasted for almost 100 years. Then in 1983, after a researcher found that this species often mates with a similar-appearing oriole of the West, Bullock’s Oriole, and produces healthy hybrid young, the two species were lumped—that is, put together – as a single species with the new name Northern Oriole.

But ongoing research since then has uncovered intriguing problems. First, the hybrids don’t survive well, probably because they molt in late summer, before migration, as Baltimore Orioles do, AND in autumn after a partial migration, as Bullock’s Orioles do. Two molts in a single season is very depleting. Also, the DNA of the two birds is quite different—now ornithologists don’t even consider them sister species! So in 1998, the Northern Oriole was split into two species, the Baltimore and Bullock’s Oriole.



Q. Do robins ever visit bird feeders?

A. American Robins don’t eat most of the things we set out in bird feeders. Some people have had great luck attracting robins to feeders by offering fruit (especially berries) or mealworms. The trick is getting the robins to notice the feeder in the first place, because in most robins’ experience, food grows on trees, or on the ground, but not in bird feeders. Very rarely, a robin will check out a feeder after noticing other birds at it. Having the feeder near where robins would normally be perching, and setting moist fruit or wriggling where they’d be most conspicuous are good approaches for encouraging robins to notice a feeding station.



Q. Why does my backyard robin sing all night long?

A. During nest building and while the female is incubating eggs, male robins have a lot of pent-up energy. Singing throughout the night helps them remind nearby robins that they own their territory, while allowing them to use daylight hours to find food and help with their parental duties.



Q. Someone said only hawks and owls have talons, but don’t all birds have claws?

A. All birds do indeed have some sort of claws at the ends of their toes—even ducks have a bit of a claw at the tip of each of their webbed toes. The claws of many species are just as sharp as those of hawks and owls. The difference is that talons are able to grab and carry things. For example, Osprey and Bald Eagles, both true hawks, use their feet to catch and carry fish—other birds that catch and carry fish to their young, such as kingfishers and puffins, use their beaks for this. Shrikes are songbirds that feed on mice, birds, and other tiny prey. They are not related to hawks or owls, so they lack talons. Instead, they kill and carry using their sharp, notched bill. Shrikes also use sharp thorns or barbed wire to help kill and hold prey!



Q. How can birds survive the extreme cold weather we’ve had this winter?

A. Tragically, a harsh winter is hard on birds, and some end up dying. The most important protection against the weather that a bird has is food: the more calories a bird can take in, the more downy feathers it can grow and the more energy it will have for shivering to maintain its body temperature. We can’t do much to protect all the birds out there, but by feeding our backyard birds we make a difference for those individuals.



Q. Do Woodpeckers get headaches?

 A. People studying ways to protect humans from head injuries, including some who design football helmets, have studied woodpeckers for hints! Why? A drumming Pileated Woodpecker slams its head into a tree trunk 20 times a second, hitting it with a force of up to 1,200 g’s, and an individual Pileated may hit trees with this power 12,000 times a day. A University of California Davis scientist named Ivan Schwab noted that this is the same impact we would suffer if we struck a wall face-first at 16 miles per hour. People exposed to similar forces in car accidents can suffer head and spinal cord trauma, broken blood vessels behind the eye, and nerve damage to the head and eyes. How do woodpeckers protect themselves?

8433572431Using high-speed photography, Dr. Schwab discovered that one millisecond before a woodpecker’s bill tip hits a tree, thick neck muscles contract, causing much of the force of the blow to radiate down the neck and to the rest of the body, protecting the brain and spinal cord. Muscles that attach the jaw to the skull also contract just before the blow, shooting the force of the blow to the back of the skull without jarring the brain itself. The bones of the skull are spongy, absorbing more shock to protect the brain than our skull can.

All birds have two sets of eyelids—the normal one and the inner “nictitating membrane.” This inner eyelid in woodpeckers is exceptionally thick. It closes over the eye a millisecond before each strike, both protecting the eye from flying bits of woodchips and restraining the eye from popping out with the impact. Internal structures within the eyeball also help maintain pressure within the eye at impact, protecting the woodpecker from breaking blood vessels in the back of its eye while drumming.

3277321828Woodpeckers are among the very few birds that can stick out their tongues. Pileated Woodpecker tongues may protrude as much as 4 inches beyond the tip of their beak when tracing tunnels created by insect larvae in the wood. Intriguingly, when pulled in, the woodpecker tongue may also help protect the skull. The tongue passes between the eyes and divides to wrap around the skull before rejoining in the mouth, almost certainly operating as a shock absorber as well as a wonderful probe for insects. So next time you see a Woodpecker stick out its tongue, don’t be offended.



Q. Why does one of my cardinals keep pecking at and flying into my window?

A. Some very smart birds, such as magpies, know that the reflection in a window or mirror is their own image. Cardinals don’t understand this; when a cardinal sees its reflection, it thinks another cardinal is on its territory and wants to chase it away. Real cardinals that see each other may fight briefly, but in winter they work out ways to be near each other without stress by keeping a distance, not looking directly at each other, and flying away if the other gets too close.

Reflected cardinals never do this. They stare and raise their crest exactly as the real cardinal does. The only way to get them to stop is to temporarily block the reflection. Papering over the window on the outside for a day or two usually works.


Q. How often should I clean my bird Feeders?

A. In normal circumstances, most bird feeders are fairly low maintenance. To keep seed fresh and safe, we should’t offer more than birds can finish in a few days, and shouldn’t allow seed to stand for long after being soaked.

If we’re using a large tube or hopper feeder and don’t have enough birds to empty it frequently, we should empty it entirely once a week. If the seed is still dry, we can scatter that for ground-feeding birds. And we should brush off platform feeders every few days, too, so that shells and uneaten seeds don’t collect beneath fresh seed. As long as the seed is fresh, feeders don’t usually require any more cleaning than simply emptying them or brushing them out. Once a year or so, it can be a good idea to thoroughly wash feeders.