September Newsletter

It is hard to believe that the Autumn Equinox is this Friday, the 22nd of September.  Warm days and cool nights, picking flowers and harvesting vegetables. I’m making lots of soup with those root vegetables and squash !
The Bird Center is slowing down, there are fewer birds, 18 as of today and most are self feeding. Hours are now 7AM to 8PM
 Volunteer Judy Lobato
“This is my 2nd season volunteering at BCWC. My shift is 7-9am on Tuesdays. I clean cages and on the rare occasion there’s extra time I wash dishes. When a call goes out for extra help, I try to participate but I volunteer with other groups, so it doesn’t always work into my busy retiree schedule.
I walk dogs at HSHV, count butterflies, twice a month I am an ESL (English as a Second Language)  conversation partner at Jewish Family Services and twice a month volunteer at Huron Valley Women’s Prison. Mix in getting enough exercise and meeting friends for breakfast or lunch- it’s a good thing I’m retired since I don’t have time to work. Fall and winter finds me following the Spartans & Steelers and spring & summer I watch the Yankees.
Life is full.
I live on 50 acres with my husband Duane Tomas and black cat Tess. We watch turkeys, sandhill cranes, fox, deer and listen to owls and coyotes.”


An excellent article that illustrates what we do at the Bird Center from intake to release, and the many many hours of work given by our incredible volunteers, interns and staff .

Clinic Case Study: Raising a Baby Blue Jay

By Michele Wellard, Assistant Wildlife Rehabilitator
On May 13, this baby blue jay, likely having fallen from his nest, was brought into the Wildlife Clinic. The people who found him couldn’t locate the nest to return him, and so they brought him to the clinic. Over the last few weeks, this little blue jay has had many people involved in his care, from dedicated volunteers to our wildlife rehabilitators. Raising a songbird baby can be a real challenge, with a particular diet, a special nest to ensure his legs grow straight, and regular feedings until he’s old enough to feed himself. At the clinic we are careful to make sure the blue jay does not become tame or imprinted, so he can be released into the wild once he’s old enough.
  These photos show the little blue jay, just two or three days old, upon admission to the clinic. Songbirds like him are born naked, blind, and helpless, and with a strong urge to “gape” (i.e. beg for food). How did we know he was a bluejay? There are several clues. His dark skin is different from other baby birds, who are often more pink. He has absolutely no fuzz on him, whereas other songbird hatchlings sometimes do. The color around his beak is pink – many songbird babies have yellow “lips” called the gape flange. The gape flange, together with the beak color inside the bird’s mouth indicate to the parents exactly where to deposit the food.
 By the second week of his life, you can see many changes starting to the blue jay’s appearance, as he grows at a rapid rate. He is fed every half an hour from sun up to sundown by clinic staff and volunteers, just as his parents would. He is fed insects, a mush called “songbird diet” and some berries. You’ll see that he has become “fuzzy” in places (right), and his wing feathers are starting to develop. At this point they are still “blood feathers” (they have a blood supply to nourish the developing feather) and look like little sticks. Tiny spurts of the beginnings of feathers are beginning to emerge from his head. He has almost doubled in weight and has gotten much bigger.
 After the second week, our little patient is starting to look more like a bird, particularly a blue jay. He has gotten some real feathers and is looking distinctively fluffy. He can hold his head upright when at rest, and those blood feathers are starting to sheath of the coating and open up at the tips. He’s also starting to get the beginning of that famous jaunty blue jay crest.
 By the third week, our little bird is becoming unmistakably a blue jay.  His wing feathers are opening more, showing a variety of white and blue. The feathers on his face are also coming in, creating his distinctive facial markings. At this stage he is still a “nestling,” too young to leave the nest.  However, he is starting to have an urge to open his wings and flap a bit.  He can’t perch yet, but should be doing so soon. Then he will be moved to a small mesh cage, with a training perch to strengthen his feet and leg muscles and give him experience perching and hopping.
On May 29, the blue jay took his first flight, fluttering for a few seconds before landing on the ground.  He’s learning to perch in his small mesh indoor aviary. He will go into an outdoor aviary in early June, and be released in late June.
 By June 12, the blue jay has moved to a larger indoor aviary.  He’s sharing space with several slightly younger blue jays now, enabling them to for social bonds and care for each other.  He’s also beginning to chase crickets and meal worms.
Volunteer Zach Mobley feeding mealworms to young Chimney Swifts.
“I am an Ann Arbor native recently moved back to the area after completing my Masters degree in Bioethics at Chicago’s Trinity International University. My interests lie in research and environmental ethics, particularly instituting regulatory programs for Controlled Substance Licensing Institutional Animal Care and Use Committees (IACUC). My professional background is in biotechnology/animal science and am currently working quality control in a chemical engineering lab. I have participated in several avian field research projects seeking out and monitoring individual nesting sites and collecting environmental data. I spent a summer in Nevada’s Virgin River Valley collecting data on the endangered Southwestern Willow Flycatcher and their threatened Salt Cedar marshland habitat. This is my first volunteer season at the Bird Center. I spend my time there administering regular feedings to hatchlings and fledglings, maintaining nest baskets, and assisting interns with medical applications. I am hoping to continue helping the center and further develop my songbird knowledge as an intern next season!
   Chimney Swift mom and 2 newborn babies in nest. It’s a precarious situation as you can see. Often roosting in residential chimneys, at times they fall out of the nest when only a few days old. Our swifts were brought to us by homeowners who discovered these tiny babies  in their fireplace.
 My granddaughter Luisa observing young swifts. They are extremely social, looking at us and chattering loudly when we came close.
 Swifts spend most of their lives on the wing, catching insects as they fly. They do not perch, but cling to vertical walls in chimneys.
Have you taken a walk or bike ride in Dexter’s Mill Creek Park ?
It’s especially beautiful at this time of year along the boardwalk.

Early August 2017 newsletter


Hard to believe it is already August. My computer needs to be retired, and I have been having problems with it, so this newsletter is late. The heavy summer heat bears down on us and we could use rain. But gardens are lush with flowers enough for picking bouquets and more than enough cucumbers to make a delicious cold summer soup.

There are 106 birds at the Center. We have plenty of Robins, several Flickers, a tiny Chipping Sparrow and 2 groups of young Chimney Swifts.
 As the season begins to wind down, some of our staff are moving on. Daniella Silver is leaving and will be travelling to Israel. Best of luck and THANK YOU for your hard work and dedication to the birds !

Good Afternoon.  Since the last update on July 19th we have received results on 14 positive animals; an American Crow from Allegan County, an American Crow from Baraga County, a Red-tailed Hawk from Eaton County, an American Woodcock from Houghton County, an American Crow from Kent County, 2 American Crows from Livingston County, a Red-tailed Hawk from Oakland County, an American Crow from Ontonagon County, an American Crow from Ottawa County, and a Common Grackle, 2 American Crows, and a Cooper’s Hawk from Wayne County.  This brings the total number of West Nile Virus positive animals in 2017 to 42 from 26 counties:

Lower Peninsula
Allegan County American Crow
Barry County Wild Turkey
Eaton County American Crow, Red-tailed Hawk
Genesee County Ivory Gull
Ingham County American Crow
Jackson County American Crow
Kalamazoo County American Crow
Kent County American Crow
Lenawee County American Crow
Livingston County Great Horned Owl, American Crow (2)
Mecosta County American Crow
Missaukee County American Crow
Oakland County Common Grackle, Red-tailed Hawk, Mallard
Ottawa County—American Crow
Shiawassee County Blue Jay
Van Buren County American Crow
Washtenaw County Green Heron
Wayne County American Robin (2), Common Grackle, American Crow (2), Coopers Hawk

Upper Peninsula
Alger County American Crow
Baraga Couny Bald Eagle, American Crow (2)
Delta County American Crow, Northern Goshawk
Houghton County American Crow, American Woodcock
Luce County American Crow (2)
Marquette County Common Raven, American Crow
Menominee County American Crow
Ontonagon County American Crow

If you receive calls from the public concerning neurologically abnormal avian species, please try to collect the bird, euthanize it if necessary, and submit it to the Lab as soon as possible for examination and testing.  Depending on the species and the clinical signs observed, we may test the bird for Avian Influenza as well.  If we confirm West Nile Virus in a species in a county, we may not test additional birds from the same species for West Nile Virus but we will still necropsy the bird if submitted for examination.

If you receive a report of a die-off of bats, please collect 3-6 specimens and we will test them for Rabies and West Nile Virus and perform a necropsy.  If you receive a report of other neurologically abnormal mammalian species, please try to collect it, euthanize it if necessary (please do not damage the brain), and submit it to us as soon as possible.  Depending on the species, we will test it for a variety of diseases (Rabies, Canine Distemper, Eastern Equine Encephalitis, West Nile Virus, etc.).  There are chapters in our Wildlife Disease Manual ( on all of these diseases if you want to read more about them.

Thank you for your assistance with the collection of specimens for testing.  I will keep you updated on West Nile Virus positive animals that we examine and if you have any questions, call me or send me an email.  Tom

Thomas M. Cooley
Wildlife Biologist/Pathologist
Michigan Department of Natural Resources
Wildlife Disease Lab
4125 Beaumont Rd.
Lansing, MI  48910

Chimney Swift
Young Chimney Swifts clinging to their mesh enclosure at the Bird Center
  • Chimney Swift
 IUCN Conservation Status: Near Threatened
A bird best identified by silhouette, the smudge-gray Chimney Swift nimbly maneuvers over rooftops, fields, and rivers to catch insects. Its tiny body, curving wings, and stiff, shallow wingbeats give it a flight style as distinctive as its fluid, chattering call. This enigmatic little bird spends almost its entire life airborne. When it lands, it can’t perch-it clings to vertical walls inside chimneys or in hollow trees or caves. This species has suffered sharp declines as chimneys fall into disuse across the continent.
Chimney Swifts eat airborne insects. Feeding on the wing, they capture flies, bugs, bees, wasps, ants, mayflies, beetles, fleas, and other insects. They grab large insects with their bills; small ones go right down the throat. Chimney Swifts feed over urban and residential neighborhoods, fields, grasslands, orchards, forests, and marshes. They can also pick insects from branch tips and “helicopter” down through the foliage to flush out prey. Normally diurnal foragers, they sometimes hunt for insects at night around streetlights or lit windows. They have been reported taking berries from elderberry bushes.
Nesting Facts
Clutch Size
3-5 eggs
Number of Broods
1-2 broods
Incubation Period
16-21 days
Nestling Period
14-19 days
Egg Description
Pure white.
Condition at Hatching
Helpless and naked.
Nest Description
The nest is a half-saucer of loosely woven twigs, stuck together and cemented to the chimney wall with the bird’s glue-like saliva. Both parents independently contribute to the nest: they break off small twigs with their feet while flying through branches, then return to the nest site with the twigs in their bills. The completed nest measures 2-3 inches from front to back, 4 inches wide, and 1 inch deep.

Although they originally nested in natural sites such as caves and hollow trees of old-growth forests, Chimney Swifts now nest primarily in chimneys and other artificial sites with vertical surfaces and low light (including air vents, old wells, abandoned cisterns, outhouses, boathouses, garages, silos, barns, lighthouses, and firewood sheds). Both members of a breeding pair may fly toward several potential nest locations, then cling side by side at one particular site, with one member of the pair giving a rhythmic chipping call.
BehaviorChimney Swifts spend their lives airborne, except when they are roosting or on the nest. They perform aerial courtship displays within 2 weeks of arriving on their North American breeding grounds, forming monogamous pairs for the season.  After the young fledge, small groups of parents and young from several chimneys join larger staging flocks in bigger chimneys nearby. At the end of summer they gather into large groups to migrate to South America. During migration, as many as 10,000 swifts may circle in a tornado-like flock at dusk and funnel into a roosting chimney to spend the night. The lives of these widespread urban birds are surprisingly unstudied, because of their inaccessible nesting and roosting sites and their aerial lifestyle.
ConservationChimney Swifts have been in a long-term, rangewide decline of about 2.5% per year between 1966 and 2015, resulting in a cumulative decline of 72%, according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 7.8 million, with 99% breeding in the U.S., and 1% in Canada. The 2014 State of the Birds Report listed the species as a Common Bird in Steep Decline.
 These birds probably became much more numerous with European settlement and the building of millions of chimneys. But traditional brick chimneys are now deteriorating and modern chimneys tend to be unsuitable for nest sites. Adding to the problem, some homeowners now cap their unused chimneys. Chimney cleaning during the nesting season can inadvertently destroy nests and kill swifts. Logging of old-growth forests can reduce the availability of natural nest sites. To prevent further decline, people may need to preserve existing chimneys or create new structures specifically for swift nesting; designs can be downloaded from the North American Chimney Swift Nest Site Research Project.
Migration    Long-distance migrant. Chimney Swifts breed in urban and suburban habitats across the eastern half of the United States and southern Canada. They spend the winter in the upper Amazon basin of Peru, Ecuador, Chile, and Brazil, Chimney Swifts migrate to South America each winter flying across the Gulf of Mexico or skirting it along the Texas coast (a route they’re more likely to take in spring than fall). Many swifts use one of three distinct flyways: the Atlantic coast, the east side of the Appalachians, and the Mississippi River. They fly high in the sky during the day and roost in chimneys at night.
Backyard Tips
Chimney Swifts may take up residence in your brick chimney if you leave the chimney cap off. It’s a good idea to keep the damper closed during summer and to schedule chimney cleanings either before or after the breeding season. If you don’t have a chimney, you can build a swift nesting tower with plans from the North American Chimney Swift Nest Site Research Project.
 The “flying cigar” silhouette of the Chimney Swift is a common sight all summer in the skies over eastern cities and towns. Lakes and rivers are especially good places to look for swifts.
You can watch the swifts settle in for the night : Go to Detroit for information about the The Swift Sanctuary to watch the daily spectacular show as up to 50,000 Chimney Swifts swirl around and around like a tornado before the avian funnel cloud swirls right down into this historic winery. A wooded area behind the historic winery abuts the Rouge River, so there may be some migrants lurking there as well. As far as we know this is THE largest roost of Chimney Swifts in North America! . Bring a lawn chair to sit and watch this incredible show. The biggest congregation of swifts in this chimney usually happens in the fall.  MID AUGUST TO END OF OCTOBER 6-9 PM
As the late summer afternoon shadows lengthen I watch a group of about 15 chimney swifts. First I hear their high chattering calls, then I watch them circling in the sky around and around until it’s dark. I don’t know where they spend the night or how far away their roost is.
Chipping Sparrow                       
 Have a splendid weekend, Perhaps a moonlight swim?

Memorial Day Newsletter

The door to the building is open-
I can hear them half a block away, loud and frantic. I can picture them, beaks wide open andnecks stretched up shoutingfeedme!feedme!feedme! And they will get fed, every 15-30 minutes. Here at the Bird Center, volunteers, interns and staff are super busy keeping up with the care of the orphaned and injured songbirds that have been brought to us.
There are 114 birds at the Center, a mix of nestlings in incubators, fledglings in mesh covered buckets, and the older birds in covered laundry baskets.
In less than 2 weeks the robins, finch and other songbird babies will transform themselves from pink skinned fuzzy nestlings to feathered fledglings and to juveniles. Then they will be transferred to a laundry basket and slowly, finally learn to be self feeding. We’re almost at capacity and it isn’t even June.
Intern Tyler Heyen, staff members Nicky Diroff and Remy Thomas, and brand new volunteer Stephanie Christau are busy cleaning baskets, feeding birds and answering the phone. Stephanie tells me she started just the day before. She found an injured robin, took it to the Humane Society and they sent her to us. She knew then and there that she wanted to volunteer and signed up on the spot! We are caring for a Horned Lark with a wing injury and a Grosbeak that has a head and shoulder injury, both birds are unable to be released and we are in contact with the Akron Zoo.
 Intern Tyler Heyen and Staff member Nicky Diroff feeding the birds.

It is with our deepest sorrow we report that the Bird Center of Washtenaw County and the rehabilitation community has lost a wonderful wildlife rehabilitator friend, and colleague.
Amanda Margraves died Saturday night in South Dade, FL.
Amanda started out her career at the Bird Center from 2005-2007 after graduating from U of M with an anthropology and zoological degree. She relocated to Georgia and then to Belize where she rehabilitated birds. She later made a home in Florida where she worked as a rehabilitater with the South Dade Wildlife Rescue Center and as a zookeeper at the Miami Zoo.
Amanda had a huge heart for animals and would go above and beyond to do anything for them. She was a big asset to the Center when it opened and to Carol Akerlof, the Center’s founder.
We send our deepest thoughts and prayers to the friends and family of Amanda as they accept this sudden sad loss. Amanda would want us to continue our mission and tend to the birds.
Thank you Amanda for all that you did.

 Every year The Bird Center
sends one of our staff members to the
 National Wildlife Rehabilitators Association Conference.
 This scholarship will be named
 the Amanda Musgraves scholarship
Staff member Daniella Silver holding a female Mallard Duck that had been hit by a car. She is recuperating well and we are hopeful that she will be released.
“I love working at the bird center because it has allowed me to become a part of a great community with a common passion for wildlife. I learn something new from my peers every day. I also learn from the birds, each one with its own personality.
This mallard laid an egg when she first came in. I call her big mama now”.


Dear Bird Center,
Have you ever been to the Nichols Arboretum Peony Garden? Hundreds of the plants are in bloom now! The garden is near the CS Mott Children’s Hospital. It’s the largest peony garden in the US.
 Take a picnic !
 Have a lovely weekend. Phyllis

This is an important and very informative article.
With spring finally here, meaning tick season has returned as well, Washtenaw County Public Health is reminding residents that Lyme disease has been detected here. The conditions exist for Lyme transmission to occur throughout the county. This is where it’s helpful for residents be aware – both to take preventative steps to prevent infection, but also to submit ticks for identification and testing.”
Lyme disease is spread by the tiny deer tick. Ticks feed on blood, and infected ticks transmit the disease as they feed. Although the deer tick prefers to feed on wild animals, especially mice, birds, opossum, raccoon, and deer, they will also feed on dogs, cats, livestock, and humans. When people visit or live near deer tick habitats, they run a high risk of contracting Lyme disease. For your own safety, you should become familiar with tick habits and habitats, and you should learn how to prevent tick bites.
Favorite Tick Habitats
Deer ticks prefer to live in the woods. Dense, mature woods with a thick undergrowth of shrubs and small trees are their favorite habitat (85%). They also are found, to a lesser degree, along the edge of the woods, where the woods meet lawns or fields. Very few (4–8%) are found in lawns, because properly mowed lawns are too hot and dry to sustain the tiny deer tick. Ticks prefer the cool, moist woodlands where they have a better chance of finding an animal host.
Where you live, your hobbies, and your habits may influence your risk of a tick bite. Notice in particular these high-risk factors:
   * yards surrounded by dense woods
   * birdbaths, birdfeeders
   * outdoor pets that come indoors
   * woodpiles, brushpiles, stone or rock walls
   * swingsets, treehouses in the woods
   * outdoor occupations: landscapers, utility line workers, farmers, etc.
   * outdoor recreation: freshwater fishing, camping, hiking, hunting, etc.
Many of these factors encourage wildlife near the home, and these animals may carry ticks. Mice in particular are known hosts of immature deer ticks and carriers of Lyme disease. Reduce, remove, or avoid these risk factors as much as possible.
Personal Protection
Outdoor pursuits need not be discontinued as long as precautions are taken to prevent a tick bite:
   * Wear light-colored clothing (ticks are easier to see).
   * Wear long pants tucked into socks.
   * Avoid tall grass and shrubby areas.
   * Widen trails through woods (to 6 feet).
   * Remove brushpiles.
   * Keep turfgrass mowed.
   * Thin out low shrub vegetation in woods.
   * Wear a tick repellent.
Repellents contain the active ingredient permethrin (Duranon, Permethrin Tick Repellent, Permanone), or N,N-diethyl-meta-tolumide, usually called DEET (Off, Cutters, Muskol, etc.)* Follow label directions; apply until clothing is damp and allow to dry. These products repel 82-100% of ticks.
Tick Identification
Seventy percent of all Lyme disease cases occur from the bite of the immature (nymph) deer tick. Before feeding, nymphs are the size of a poppy seed with a dark head and translucent body. After feeding, they swell and appear dark gray and round, about the size of a mustard seed.
Adult deer ticks are the size of a sesame seed before feeding; females have a black head and brick red abdomen. After feeding, they turn gray and swell to the size of a sunflower seed kernel.
Deer ticks are active all year round, as long as the temperature is over 35°F. Peak activity months are May-June (nymphs), and October-November (adults).
Ask your county extension agent for a free copy of the bulletin “Protect Yourself from Ticks and Lyme Disease” for specific ways to identify different ticks.
Finding and Removing Ticks
Ticks don’t fly, jump, or drop from trees. They inhabit shrubby vegetation (nymphs: four- to six-inch vegetation; adults: waist-high vegetation) and wait for an animal to brush by. They then grasp the animal’s fur or skin, and crawl up the body. Ticks will wander on the body for 30-60 minutes before they insert their mouth-parts and begin to feed.
INFECTED DEER TICKS MUST FEED FOR AT LEAST 12 TO 24 HOURS before they can begin to transmit the Lyme disease bacterium. Therefore you should remove ticks as soon as possible. Take a shower after outdoor activity and check your body thoroughly, paying close attention to the armpits, the groin, and neck. Use the buddy system! Look for ticks nightly, especially if you have young children.
Remove ticks with tweezers only (bent, “needle-nose” tweezers are best). Do not use alcohol, nail polish, hot matches, petroleum jelly, or other methods to remove ticks. These methods may actually traumatize ticks, causing them to regurgitate gut contents, which may include the Lyme disease bacterium.
More information about Lyme disease and tick-borne disease prevention is available on the county’s website.
Washtenaw County Public Health encourages residents to submit ticks for identification, noting blacklegged ticks found in Washtenaw County tested positive for the Lyme pathogen in 2016.
The more local ticks are tested, the better the county will know how widespread the risk of Lyme disease is in different areas of the county.
The state also has a program to identify ticks, and if it is a live blacklegged tick, test for Lyme disease. Information is available on the state’s website.
Ask your county extension agent for a free copy of the bulletin “Protect Yourself from Ticks and Lyme Disease” for specific ways to identify different ticks.

Early April Newsletter

Early April 2017 newsletter
Our 13th year of saving wild birds

Dear Friends,
The Bird Center will be open and staffed starting Monday May 8th at 7AM!
The migrating birds are coming back, and I hear lots of birdsong and activity. We have a few more birds at the Center: a cardinal, a dove, a titmouse, and a junco. We are receiving email requests for volunteer applications. We’re getting ready for the new season.

2017 Volunteer Orientation
We need volunteers to help care for and feed young and injured song birds for our 2017 season May-September at our Ann Arbor, MI location. Please join us for our Volunteer Orientation on Saturday, April 29 from 9:30 – 12 noon.
Room 319 in the Gunder Myran Building at Washtenaw Community College campus.  We will discuss our organization and volunteer opportunities.

Flyaway, our annual Bird Center fundraiser and silent auction, took place the evening of March 28th at the Matthaei Botanical Garden’s Conservatory.
From 7 to 10 PM guests wandered through the candlelit tropical and desert gardens and enjoyed the delicious buffet.  The silent auction was a great success. We were honored to have Yousef Rabhi, MI State Rep (D-Ann Arbor) as our speaker. Rep. Rabhi enthusiastically supports the Bird Center’s continuing work of protecting wild birds and the environment through our rehabilitation and education programs.
❦   Carol Akerlof, Director and founder of the Bird Center of Washtenaw County, is retiring after 13 years of devoted work on behalf of our local wild songbirds. Thank you from all of us at the Bird Center, Carol, and
thank you from the birds.
Juvenile Cedar Waxwings
   Board member Molly Osler presenting Carol Akerlof with a gift basket.
She received chocolate (Carol’s favorite!)and a beautiful silk scarf made by Carol Furtado, Ann Arbor fiber artist and long time supporter of our work.
  Staff member Daniela Silver with our educational bird, Blue.
Board member Bee Friedlander introducing MI State Rep. Yousef Rabhi.
Staff members Seana Florida and Rachel Gumpper
Rachel with her silent auction purchase,
a Polish paper cutout.
Beautiful! Bee and Molly present Staff                                                                   member Gabby Costello with  an orchid.
Board member Georgette Hansen enjoying some tasty food.
Koi in the Conservatory fish pond

How Different Spring Migrants Decide When to Head North
Will warmer weather bring the birds back early? It all depends on what type of migrators they are.
By Kenn Kaufman
Spring officially started March 20, but for many of us it had already begun. Back in February, unseasonably warm temperatures swept over much of North America, buds began opening on trees, and flowers began to bloom weeks early. Naturally, birders began to ask: Will our migratory birds come back earlier, too?
That question doesn’t have a simple yes or no answer because the timing of bird migration is . . . complicated. Every species is slightly different; short-term changes in weather do have an impact, but so do a variety of other innate and environmental factors. Here’s a quick primer on how North American avians schedule their spring journeys to aid in your own birding ventures.
Two Types of Migrants
To figure out how migrating birds could be affected by balmy weather, we should start by categorizing them into two groups: obligate and facultative (to use the fancy terms). These labels aren’t ironclad-many birds fall somewhere between these extremes-but the definitions are helpful in understanding what triggers a species’ migration.  For obligate migrants, the timing of travel is dictated by hard-wired instinct. An unusually warm or cool season won’t make them suddenly decide to change their departure dates. They’ll move at about the same time each year, regardless of weather. Meanwhile, facultative migrants are more tuned in to the conditions of the moment. They have a standard timing for their migration, but they might tweak it by days, or even weeks, if the season is chillier or more temperate than usual. They’re flexible.
So how does this work during spring migration? When birds start moving north from their winter homes, the hard-wired, obligate migrants run like clockwork. That includes certain songbirds, raptors, shorebirds, and others that commute between the far north and the deep tropics or temperate southern zone. A Blackburnian Warbler spending the winter in South America or a Wood Thrush wintering in Costa Rica won’t have any way to judge what’s happening up the United States and Canada. Such species may wait for clear skies and favorable winds to launch each stage in their journey, but a major warm spell won’t cue an early arrival.
Meanwhile, most of the flexible, facultative migrants are birds that only move short distances, wintering right in the United States. This allows them to sense local conditions and seize opportunities to move closer to their breeding grounds. Overall weather patterns tend to apply to broad regions, so if the season continues to be warm, facultative birds may gradually move north ahead of schedule. For example, if the weather is mild in late February, a Fox Sparrow in Tennessee might guess that life won’t be too bad a few hundred miles farther up in Ohio. Red-winged Blackbirds, Common Grackles, American Woodcocks, Killdeers, Eastern Phoebes, and even Tree Swallows are other species that may turn up earlier than average during a warm spring.
Most parulids (new world warblers) winter deep in the tropics, and the timing of their northward migration is dictated by instinct. Yellow-rumped Warblers, however, may be more flexible because they mainly winter in the southern United States. Thinking of birds this way makes it easier to predict their arrival. Will the warblers come back early this year? Yellow-rumped Warblers might, because they’re short-distance migrants, wintering mostly in the southern states. Hooded Warblers won’t, because they’re obligate migrants, wintering deep in the tropics.
It’s even easier to understand the difference if we also consider fall migration. Among obligate migrants in North America, Orchard Orioles may start their southward journeys in July, and Yellow Warblers may travel south in August. At that time the weather is still pleasant and food is abundant, so obviously these birds aren’t driven out by cold weather-they just go when instinct tells them to. By contrast, facultative migrants may linger until conditions egg them on. Ducks, geese, and swans need open water, and although some migrate early, others may stay north until their habitat freezes over. The severity of the season may even influence how far south they go for the winter. The Sandhill Crane is another good example of a facultative migrant; in recent years, some Sandhill populations have been migrating later in fall and earlier in spring, while spending the winter farther north than they ever had in the past.
Waterfowl like these Tundra Swans have a typical window of time for their migrations, but they also need open water. An unusually cold spring may delay their northward migration until their habitat thaws.
Built-in Adaptability
Now, if a bird is a stickler for schedule, can it change its migration timing? Yes, but not in its lifetime: The species will make the shift over multiple generations. As with any other instinctive behavior, migration windows can evolve over time. That adaptability is based on survival.
The perfect time for a bird to arrive on its breeding grounds is a balance of two pressures. On one hand, it needs to arrive early to claim prime territory. On the other hand, if it moves north too far or too fast, it might freeze or starve. In every population of migratory birds, individuals vary somewhat in their timing. Those that hit the sweet spot and arrive at the perfect time are more likely to nest and raise young successfully, so their genes are more likely to be passed along to the next generation.
If the climate changes so that warm spring temperatures creep up earlier, birds that arrive earlier may have the advantage. Not only will the early bird get the worm, it may also get the best territory and the healthiest mate and raise more young than its slowpoke neighbors. If the genes for early migration are passed along to more of the offspring, then over a span of many generations, the average timing of arrival of the entire population will gradually shift. Other factors could be at work as well: For example, one study of Black-tailed Godwits suggests that females will lay eggs earlier in a warmer season, and that young birds that hatch at the beginning of the summer will migrate earlier the next spring.
Scientists are still working to understand just how different species can alter their travel calendars. But with rapid climate change already under way, the concern is that some migratory birds may not be able to evolve quickly enough to keep up. You can pitch in and help experts keep track of these patterns by plugging your spring-migration sightings into databases like eBird and Audubon’s Hummingbirds at Home.

Thank you to everyone who has offered to help. We should be in good shape for a smooth transition to the Ann Arbor Animal Hospital and back again.

The finches are back!

Actually they have been back a few weeks!


They probably deserve our care and feeding in this last winter storm!

About Goldfinches:

Bird feeding background: