birds

September 22, 2025: Just passing through

Posted on by Tim

September is one of the best months for birding in much of the United States. That’s definitely true in Forsyth County, North Carolina. Birders like me wake up at dawn most days this month to go stare into the trees. We’re hoping to catch a glimpse of migrating songbirds. Each year, billions of these guys travel from the Northern U.S. and Canada to the Caribbean, Mexico, Central, and even South America and back. Folks in the middle of the country get two shots a year to see them—spring as they hasten north toward breeding grounds, and fall, as they make their way back south. Some species take different routes on their northern and southern journeys, so it’s definitely worth it to bird during both!

All songbirds forage during the day, however they mostly migrate at night. When the winds are right, millions of birds can pass over favored corridors each night. Amazing, their movements are detectable on Doppler radar. The folks at Cornell, in collaboration with Colorado State and UMass Amherst, take that radar data and publish real time and predictive models for each night about where and in which direction migrants are. The predictive capabilities of BirdCast are an amazing conservation tool, as they allow the issuing of “lights out” warnings. Migrating birds can be easily disoriented by light pollution, and getting folks to turn off lights, especially in tall buildings on heavy migration days, can dramatically improve survivorship. The forecast is also helpful for knowing what days might be the best for finding birds the next morning.

In the weeks before I needed to head back to California, and in between trips to the coast, the mountains, and Pennsylvania, I submitted 23 eBird checklists from Forsyth County. Across these lists I found 16 different species of songbirds that don’t breed or winter anywhere in the county—definite migrants. This list included Warbling Vireo, Baltimore Oriole, Gray-cheeked Thrush, and an amazing 13 species of warbler:

Worm-Eating Warbler

Golden-winged Warbler

Blue-winged Warbler

Tennessee Warbler

Cape May Warbler

Magnolia Warbler

Bay-breasted Warbler

Blackburnian Warbler

Chestnut-Sided Warbler

Black-throated Blue Warbler

Palm Warbler

Black-throated Green Warbler

Canada Warbler

While that’s a pretty good list, there are 36 species of warbler that have been seen in the county, and I’ve only seen 24. Finding the rest is a great motivation to keep peering into trees for many Septembers to come.

June 22, 2025: Summer Backyard Birding

Posted on by Tim

Today is the last day before I head back to California, and a beautiful, warm morning for a feeder watch. The last northern-bound migrants finished passing through Forsyth county a few weeks ago. We currently only have breeding birds until shorebird migration and post breeding dispersal begin again in a month. Landbird migration will follow, not beginning in earnest until late-August. Overall, the backyard has been a bit quieter lately. While there still is a decent dawn chorus, the heat and the business of raising families has reduced a lot of the singing in the middle of the day. Birding is definitely now an early morning activity.

6:00 Start of observation hour. Already Song Sparrow, Carolina Wren, Tufted Titmouse and American Robin singing. Within the first minute, I also hear a Blue Jay and Common Grackle call.

6:02 A Gray Catbird flies into the yard. A House Finch and an Eastern Towhee call.

6:04 A European Starling flies over. A Tufted Titmousegrabs a seed from the feeder—my first customer of the morning.

6:05 Dawn officially breaks. A Northern Cardinal joins the morning chorus.

6:06 I hear a distant Mourning Dove and Downy Woodpecker.

6:08 Two male robins aggressively chase each other through the year.

6:12 A catbird visits the platform feeder. This feeder is new addition to our backyard array, and while setting out oranges on it to attract orioles has been a bust so far, it’s a big hit with the catbirds and towhees.

6:13 A Great Crested Flycatcher flies into the top of our acacia tree and begins calling loudly. We didn’t see this species last summer, but one bird has been hanging around the front yard since late May.

6:17 A Chimney Swift flies low overhead

6:22 The finches and cardinals are singing vociferously

6:25 A White-Breasted Nuthatch flies into our walnut tree and descends to the feeder

6:26 I spot a newly fledged robin in our oak, its spotted breast blending in well in the dappled light.

6:29 Brown-Headed Nuthatches are calling from the neighbor’s yard. They’ve been mostly absent all summer until showing back up a couple days ago.

6:32 A few American Crows fly by calling

6:33 A cicada begins calling briefly. A sure sign of summer, they started their clamorous chorus in earnest about a week ago.

6:35 Grackles and Blue Jays descend into the yard.

6:35 A Carolina Chickadee begins calling.

6:37 I spot a Great Blue Heron flying high overhead.

6:45 An Eastern Bluebird family (male, female, and fledgling) are in an oak tree across the street

6:50 The Downy Woodpecker comes to the feeder, and pigs out on seeds for the remainder of the watch

6:58 I walk to the back of the yard, and in quick succession hear a Fish Crow, Red-Bellied Woodpecker and spot a Brown Thrasher, the last birds of the watch.

Total: 24 Species.

Most notable: Great Blue Heron. While common in the area, we don’t really have any nearby wetlands or open fields nearby, which are the typical haunts of this species. This is the first time I’ve seen a heron (of any kind) from our place—and it’s my 57th species for the yard.

Strangest misses: The Red-bellied Woodpecker and Brown Thrasher I identified in the closing seconds would have both been big misses, as they are quite common summer residents. The local birds of both species have already fledged chicks, and are therefore keeping a lower profile than in the spring, when they were calling and singing almost constantly. Probably the next most likely bird that I didn’t see is a Northern Flicker. I see them most days, but it’s not strange at all to go an hour without one. A Brown-headed Cowbird visited the platform feeder 20 minutes after my watch ended.

Comparisons: As expected, I totaled fewer birds than spring, but more than winter. Nineteen birds overlapped with the spring watch, and five birds were new.

April 25th, 2025: Measuring Migration

Posted on by Tim

California spring is very much in full swing, and most of the migratory breeding birds have returned to the state. However, every year it takes me some time to track down all the new arrivals. I thought it would be fun to talk a bit about the migratory species that I found for the first time this year during my stay at Sedgwick Reserve, in Santa Barbara County, California. I’ll order them by how far they’ve come to get here.

Tricolored Blackbirds are a threated species is almost exclusively found in California throughout the year. They are nomadic, moving around the Central Valley in the winter. Many stay there to breed in marshes and croplands, sometimes in colonies of tens of thousands. A few hundred birds breed at Sedgwick, making the short trip every March to a small cattail-filled pond they share with Red-winged Blackbirds. Strangely, the two blackbird species seem to have divided the pond down the middle with very little intraspecies conflict–Trikes to the north, Red-wings to the south

Costa’s Hummingbirds also migrate to Santa Barbara from just a couple counties over. The closest locations that regularly have this species in the winter are the sage scrub covered hills above Los Angeles. In springs when the desert super blooms, most Costa’s will take advantage of all the delicious nectar and spend the spring and early summer there. In these years of bounty they can double or even triple clutch. This year saw extremely low precipitation across the desert. Therefore, more Costa’s may end up wandering west rather than staying east.

Lawrence’s Goldfinchs are another nomadic species. They tend to winter in the deserts of California and Arizona, returning to the oak woodlands that ring the Central Valley in March. However, their numbers at any one place fluctuate wildly from year to year as they follow large blooms of their favorite food–fiddleneck (Amsinckia)seeds. Despite far below average rainfall here, it strangely seems to be a good year for both fiddleneck and finches. As the fiddleneck finishes setting seed, some of them may follow the bloom into Northern California before heading back east for the winter.

Lazuli Buntings have just recently joined us here from the weedy fields and thorn scrub of nearby western Mexico. In southern California, they like brushy hillsides, and seem to do quite well in recently burned areas. Each beautiful turquoise and ochre male sings an individualized three-part song in hopes of attracting an extremely drab-colored female. Once breeding is over, Lazuli Buntings will fly to Southeast Arizona or neighboring Sonora for fall, where they’ll molt while chowing down on the seeds and bugs produced by the summer monsoons there. At the end of fall, they’ll head southwest, completing their unique triangle migration.

A few Bullock’s Orioles winter in coastal southern California, but most likely the ones I’m seeing here arrived a few weeks ago from woodlands in central Mexico. They are already hard at work building their hanging, woven nests. California Lace Lichen seems to be a key component, but one I found by the barn has also integrated some nylon rope and shreds of tarp. Bullock’s Orioles primarily breed in cottonwood trees throughout much of their range, but in California, they also nest in Valley Oaks and Sycamores. The important requirements are big, widely-spaced trees full of lots of tasty caterpillars.

Black-headed Grosbeaks also like foraging in and singing from the tree tops, but a closed canopy forest or suburban garden suits them better than the open savannah here at Sedgwick. The male I saw stopping for a bath at one of the station water-features was probably planning to continue on. The final destination could be as close as the forests just up the road or as far as Southern British Columbia. He was coming from somewhere in central Mexico, where some of his kin are resident, never bothering to take the trip north.

Black-throated Gray Warblers and MacGillivray’s Warblers have similar ranges to the Grosbeak, both in winter as well as summer. Both warblers, like the Grosbeak, are just passing through the area to points north. However, their preferred habitats are quite different. Rather than tall broadleaf trees, Black-throated Grays prefer open pine forests with a brushy understory, and MacGillivray’s like streamside thickets of willows. They also eat different things. A gross (fat) beak is great for crushing fruits and berries, while a tweezer-shaped warbler beak is perfect for finding little spiders and other bugs amongst the leaves.

Western Kingbirds flew in from somewhere from Southern Mexico or Central America a few weeks ago. Here, they joined the closely related Cassin’s Kingbirds who had previously made the much shorter journey from Baja. Despite their aggressive attacks on other members of their species, and even birds of prey, the two species seem to leave each other alone. I’ve never seen a Western go after a Cassin’s or vice versa.

Western Wood-Pewees make among the longest journeys of the songbirds that breed in Southern California. They all winter in forests in northwestern South America, where they possibly spend time with their close relative, the Eastern Wood-Pewee. We actually don’t fully know how much the winter ranges of the two species overlap, because they look extremely similar and tend not to use their distinctive voices while overwintering. It’s also unclear what’s wrong with all the seemingly suitable habitat found throughout central America. The long commute makes them one of the later species to make it to their breeding grounds. The one individual spotted at Sedgwick during my week there was a vanguard of the main force that will arrive in early May.

February 25: Listing Toward Spring

Posted on by Tim

Across most of the United States, February is a boring month for birders. We’ve been stuck with the same species all winter, with no hope of reinforcements in the form of migrants until the end of March. As I wait for spring, and it’s associated turnover of species I decided to do a bit of housekeeping of my birding life list.

I’ve mentioned this before, but eBird is an absolutely amazing website for birders. It’s great for finding places to look for birds, checking recent submissions for any nearby rare or unusual birds, and linking to pictures and descriptions to help with identification. But most of all, eBird amazing at keeping lists. Listing birds is like other collecting hobby, in that more is better, complete sets or rarities are particularly fun, and conversations about which ones you have is extremely tedious to anyone who doesn’t collect. I think the difference between baseball cards or coins and birds, though, is that each item on my life list has at least one amazing memory attached to it. I’ll occasionally peruse my list and reflect on the time I saw a Great Grey Owl hunting voles in the evening light or watched a Great Curassow stride through Mayan Ruins.

Since I began using eBird in 2013, I’ve encountered (seen or heard) and logged 976 species of birds globally, 601 in the United States, and 412 in California. The problem is that I’ve seen some birds before 2013 and not since. I know for sure I’ve actually met 612 kinds in the US and 419 in California. A few of these “extra” birds are quite rare in the region, and I’ll be unlikely to ever see them there again. Therefore, in order to preserve my memories, I keep an excel spreadsheet with my USA and CA life lists. It’s easy to do in theory, but in practice, my “count” keeps changing!

Other than seeing new birds, the numbers on my list can change for two reasons. One is taxonomic change—lumping and splitting species. Based on the most recent literature, sometimes two or more species are grouped into just one. A recent example is that Common and Hoary Redpolls were found to freely interbreed, and therefore lumped into “Redpoll”. More frequently, what was formerly considered geographic variation within a species is deemed enough to elevate populations into to two or more separate species. For instance, last year Cory’s and Scopoli’s Shearwaters were split, and, as I had seen both, I got to add one to my count—an armchair tick! Numbers can also change based on which non-native species are considered “countable”. The American Birding Association (ABA, aka the birding police) keeps track of wild, but introduced populations of birds in the US and Canada, determining when they are “naturalized”—that is self-sustaining through reproduction in the wild—and thus countable. The chicken you watched crossing the road after escaping its coop doesn’t count, but the European Starling at your backyard feeder definitely does. The flock of Egyptian Geese that Jenny and I saw along the Colorado River in Austin last week? The ABA needs to make a ruling (it’s on my list, but it’s technically still a provisional species!). Finally, adding to the confusion are name changes and taxonomic revisions that alter the order birds appear of the list.

All this to say, a couple days ago I redownloaded the most recent ABA checklist, and spend a couple hours updating my excel sheet. I made adjustments to the taxonomy and additionally added the ABA rarity codes to my list. Here’s how those work:

There are 1109 species of extant (not-extinct or locally extirpated) bird species that can be counted the US, of which I’ve only seen 55%. However, 362 of those are rarities—codes 3, 4, or 5. Of those, I’ve only seen 19 (5%, including my one code 5 lifer, a White-chinned Petrel that hung out with me on a boat trip in Monterey Bay). I’ve seen about 45% of the 257 code 2 birds. Many of my code two misses would either require trips to Alaska, Hawaii, or South Texas (places I’ve never been), or are naturalized species locally found in cities (places I don’t particularly enjoy birding). That leaves the 489 code 1 birds. Of those, I’m only missing 15 (3%)! Those elusive few make a great list to search for on future adventures! Hopefully I can find a few more lifers once winter turns to spring.

January 11: Snowy Morning Feeder Watch

Posted on by Tim

A big winter storm hit Winston-Salem on the night of January 10, dumping a few inches of snow onto our yard. The next morning was forecast to be sunny and calm—perfect snow day conditions! I decided to wake up early and do an hour-long bird feeder watch, beginning just before first light. Here is my log from that watch:

7:00 am: Begin observation

7:07 First bird—Marty the Northern Mockingbird perches on the lip of our raised flower bed

7:14 Northern Cardinal calls

7:16 Marty snacks on some bark butter I had smeared on a tree trunk

7:17 Yellow-Bellied Sapsucker calls

7:19 White-Throated Sparrow and Dark Eyed Junco flock arrives, a junco snags some bark butter

7:23 American Crow calls

7:24 Ruby-Crowned Kinglet arrives, snags some bark butter

7:25 Carolina Chickadee begins chattering, and then visits the main feeder—the first bird to do so.

7:26 Tufted Titmouse and White-Breasted Nuthatch calling in the trees overhead

7:28 Carolina Wren begins singing vigorously, then eats some bark butter and fights with another wren

A Carolina Wren visits a smear of bark butter in the snow

7:31 Sunrise

7:38 A flock of House Finches and American Goldfinches flies overhead, calling. A Blue Jay flies into the magnolia tree and begins yelling at everyone

7:43 Golden-Crowned Kinglet and Yellow-Rumped Warbler briefly stop by the yard, joining the flock of activity

7:50 Marty the Mockingbird perches on top of the feeder and begins chasing away other birds

7:57 Song Sparrow sings from the bushes at the back of the yard

7:59 Carolina Wren visits our small window feeder, so far, the only species I’ve seen do so since we put it up last week.

8:00 Mourning Dove flies by, the final species to make the count. End observation.

Total: 18 species

Most notable: Yellow-Rumped Warbler. A bunch of them winter in our area, but they don’t come to our back yard that often

Strangest miss: Downy and Red-Bellied Woodpeckers are usually around, and both showed up later in the day. Eastern Bluebirds are also common in our backyard, but they tend to visit us in the afternoons.

While I very much enjoyed my time, one hour-long watch by itself isn’t particularly laden with importance. The power of careful observation comes with time and repetition. Since moving here in March, I’ve now submitted 21 eBird checklists from our backyard and seen or heard 48 species. I’m starting to get a sense of what’s “normal”. As the seasons go by, it’s exciting to see migratory birds arriving and leaving, behaviors changing, birds molting, and fledglings appearing on the scene. My plan is to repeat my dawn feeder watch three more times this year. I’m excited to compare and contrast these seasonal benchmarks.

Zooming out, my hour-long observation becomes one data point out of the 103 million checklists submitted to eBird. These checklists come from over 1 million birders from across the world. At this scale, scientists can see patterns of migration, habitat use, and population increases and declines. The data helps inform important conservation decisions and even legislation. Not bad for a snowy morning spent in front of a window.

December 23: Biases.

Posted on by Tim

This year, I’ve decided to keep a nature journal. As I already have this (previously dormant) blog, I’ve decided I’ll just post my entries on here. The plan is to write once a week, loosely basing my entries off prompts from Margaret Renkl’s new book Leaf, Cloud, Crow.

Here’s my first entry:

Our backyard has a tyrant. Marty the Northern Mockingbird is the undisputed despot of our birdfeeder. A flash of white and a flutter of wings mean that Marty has once again descended from a high oak or holly branch to reign terror upon all feathered foes. Yet again, another poor bird is prevented from nabbing a tasty sunflower seed or nutritious bit of suet. What a jerk!

Marty

I’m not proud of it, but it’s time to admit to everyone that I’m biased against mockingbirds. They are extremely loud vocalists, especially in the spring, with the annoying habit of beginning their continuous singing before sunrise They are common in suburban landscapes; thus, if I’m seeing a lot of them, it means I’m not in my preferred wilderness habitat. Plus, I really do hate a bully.

I readily admit feeling animosity toward Marty and kin is ridiculous. Mockingbirds have a lot to like. As both their common name and scientific epithet (Mimus polyglottos, the many-tongued mimic) imply, they have the amazing ability to incorporate the songs of other birds, frog calls, or even car alarms into their acoustic repertoire. While omnivorous, they are important seed dispersers of native plants, especially in fall and winter, as their diet shifts to mainly fruit. And they are willing to fearlessly take on potential predators, harassing hawks and ousting owls. I seem to be quite alone in my distain for the species, as evidenced by numerous positive references in art and literature (think, To Kill a Mockingbird). In fact, five US states have chosen the mockingbird as their official bird, trailing only beloved cardinals and meadowlarks by that popularity metric. Even Marty specifically has an admirer. My partner loves watching Marty splashing around in the bird bath that is the outside dog bowl, or hopping from fence to tree-trunk and back, head cocked at a jaunty angle, or scampering across our outdoor table, feet pattering and golden eye gleaming intelligently.

What is going on inside Marty’s little bird brain? After an hour of observation, I began to wonder if this bird is, like me, a biased creature. I started to think Marty wasn’t treating all birds equally. Carolina Wrens, in particular, seem to invoke Marty’s wrath. When a wren stopped by, not only did Marty immediately swoop in with wings outstretched, a chase often ensued, with both birds acrobatically weaving chaotically across the backyard. While Marty often displaced finches, nuthatches, and titmice from the feeder, both the intensity and duration of the rage appeared greater when a wren is involved. At the other end of the spectrum, Carolina Chickadees seemed to get a free pass as they snuck seed after seed right out from under Marty’s watchful gaze.

I wonder what forces are driving Marty’s differential treatment of competitors. Maybe Carolina Wrens, another common omnivorous resident here in North Carolina’s suburbs, share more overlap in diet, habitat, and behavior with mockingbirds than any other species. If so, then it would make evolutionary sense for Marty to pay more attention to their biggest rival! But before I build a complicated story that explains Marty’s actions, I need to check my facts. Is Marty really chasing wrens more aggressively and more often than any other species? Or are my observations of Marty’s biases themselves biased?

I came up with my wren prediction based on some initial observations. Without rigorously collecting additional data, I may subconsciously favor evidence that supports my claim. This tendency of conformation bias is why we shouldn’t just rely on antidotes when stating conclusions. In fact, as I continued to watch, Marty began aggressively chasing Eastern Bluebirds, a species that simply wasn’t around earlier in the morning. I also started noticing times when a wren snuck an unmolested snack.

So is Marty biased? In order to test my hypothesis, I would need many more observations of interactions between Marty and each species of bird. I could then statistically test if the likelihood of being chased off the feeder by the mockingbird depended on species. I probably would also need to account for things like the time of day, the length of the visit, and the number of other birds present. Then, if I wanted to make the claim that all mockingbirds (not just Marty) were biased in which species they chase, I would need to watch different mockingbirds across multiple locations. And even after all that, I still couldn’t be 100% certain in my claims. This time-consuming process is why people can get annoyed with scientists. We can’t quickly give a straight answer without couching it with an “it seems” or a “probably!” But it’s also why people can trust the conclusions of peer reviewed studies much more than their own gut feeling or the claims of a TV talking-head. We systematically eliminate sources of observational bias to get closer to the objective truth. What’s more–this careful accounting of the natural world has great side effect. It almost inevitably leads to a greater appreciation of the being you are watching. Even after just a morning of observation, I can already conclude that Marty is more beautiful, charismatic, and maybe even benevolent than my biased perspective initially had me believe.