In courtship: When a male is courting a female he rushes at her and she jumps straight up. If he’s really interested in her he’ll spray urine. You have to be a female cottontail to appreciate this.
For dominance: Rabbits are territorial about food so when two cottontails of the same sex want the same territory, they chase each other.
Fun Fact:
Cottontails are rarely found foraging for food on windy days, because the wind interferes with their hearing capabilities. Hearing incoming predators before they get close enough to attack is their primary defense mechanism.
My reflection in a Christmas ornament at Phipps Conservatory, 16 Dec 2025 (photo by Kate St. John)
20 December 2025
After Sunday’s 6″ of snow, the snow melted midweek (Wednesday’s high up to 60°F), a windy cold front arrived on Friday, and this morning it was 15°F at dawn. In the meantime I found reflections, animal tracks, and an unusual song sparrow.
Reflections: My own reflection in a Christmas ornament, plus the first hint of Thursday’s spectacular sunrise in a reflection outside my window.
Red sunrise reflected on an apartment building’s windows, Pittsburgh, 18 Dec 2025 (photo by Kate St. John)
Here’s the sunrise that made that reflection.
Sunrise in Pittsburgh, 18 Dec 2025 (photo by Kate St. John)
Tracks in the Snow, 17 December: What are these tracks below the bird feeders at Frick Park? Every set is an arc of four splats (two paws per splat), and the animal seems to wander.
Virginia opossum tracks near feeders at Frick Park, 17 Dec 2025 (photo by Kate St. John)
A closer look at the opossum tracks at Frick, 17 Dec 2025 (photos by Kate St. John)
A Collared Nape: [“Nape” is the back of the bird’s neck.]
On Tuesday I encountered a song sparrow who was not afraid to get close so I decided to photograph him with my cellphone. That’s when I realized his white collar is not snow stuck to feathers. It is actually leucistic feathers on his nape. Here he is from different angles.
Song sparrow forages near me at Schenley Park, 16 Dec 2025 (photo by Kate St. John)Song sparrow with leucistic feathers on its nape, 16 Dec 2025 (photo by Kate St. John)Song sparrow with leucistic feathers on its nape, 16 Dec 2025 (photo by Kate St. John)
Cottontail rabbit after it snowed in a Squirrel Hill backyard, Dec 2025 (photo by an anonymous friend)
12 December 2025
The eastern cottontail population in my city neighborhood comes and goes. In some years we have so many rabbits in late summer that they scuttle in front of us during the day. In other years we rarely see one. Their ebb and flow is directly related to the presence of red-tailed hawks and owls who eat them, and to the time of year. We see lots of rabbits in late summer when the young disperse and few in winter.
So where do rabbits go in winter?
A Squirrel Hill friend of mine found out. She usually doesn’t see rabbits in her yard but one showed up in late October to shelter under the ninebark bush outside her window (photo below). For several weeks he visited every 3 or 4 days. He probably he had other daytime protected spots around the neighborhood.
Cottontail rabbit before it snowed in a Squirrel Hill backyard, Nov 2025 (photo by an anonymous friend)
But this week, she writes, “Now that all the leaves are down the landscaping crews have been removing every bit of downed litter. Many, but not all, the yards are cleaner than my carpets. The cottontail has been under my tree for 5 days running.” (photo at top)
As winter progresses suitable cover becomes increasingly scarce everywhere, in the wild and in backyards. Vermont Fish and Wildlife explains (paraphrased):
Winter is the most difficult time of year for rabbits.
In Vermont, snow cover limits the distribution and densities of the cottontail population. Because they are poorly camouflaged in snow, winter cover needs are acute for cottontails. They depend on low growing woody vegetation for food as well as for escape and thermal cover.
Cottontails will select areas of better cover over areas with abundant food if both are not found together. Rabbits have two different cover requirements: feeding cover and resting/escape cover. Dense vegetation can provide adequate summer cover, but in order for the rabbit to survive the Vermont winters, dense woody vegetation(*) such as that found in old fields is critical.
Eastern cottontails are active day and night year-round. They spend their days resting on “form,” or small, scratched out depressions in clumps of grass or under brush piles. During the night or during periods of heavy snow, cottontails may use underground dens of woodchucks as temporary shelter.
Fifteen years ago, in December 2010, I wondered where rabbits went in the winter so I asked readers to comment on this article and tell me what they’d seen.
When rabbits shelter in backyards they may be under bushes, under a low deck, in woodchuck holes, or even in those large black ribbed plastic coils used for runoff.
Rabbits favor backyards with bird feeders because they eat the fallen seeds at night. They’ll also eat handouts such as carrots.
Some rabbits appear at dusk, others prefer late night forays after 10pm.
When there’s snow cover people figure out where the rabbits are by looking for their tracks. Hawks and owls do the same. I swear some rabbits are smart about this and walk on the snowless patches so you can’t track them.
Rabbits’ natural winter food is woody stems which they eat as far up as they can reach. If you have rabbits you will have to protect shrubs and young trees; rabbits girdle them.
If you have a dog that likes to chase rabbits, you will know exactly where those rabbits are!
On the subject of dogs, my favorite comment in the December 2010 blog was from Anne Curtis:
There’s at least one rabbit that is out off Beeler St. at about 11:30 pm in my front yard, because that’s the last time I take our dog out for the night, and it torments her by standing there, saying “I’m a statue and you can’t see me!” but of course she can from the contrast! No bunny tracks in the back, but lots of (feral) cat tracks. Hmmm? A connection?
Yesterday it was cloudy and cold when seven of us gathered at Duck Hollow. While we looked for birds we found several surprises.
Six of us at Duck Hollow, 30 Nov 2025, 8:30am (photo by Joe Fedor)
Most amazing was the very fat rusty-orange fox squirrel (at top) who posed like a Buddha — the fattest squirrel I’ve ever seen. I’ll bet he’s overeating at a feeder in the Duck Hollow neighborhood.
The immature tundra swan first seen in mid-November was still present, though far across the river. After our group broke up Ed McKaveny crossed the Monongahela for a closer look.
That’s when I put in my Wish for two more raptor species including my favorite bird
We saw a red-tailed hawk, as I expected, but where was the peregrine I’ve seen at Duck Hollow since November?
After more than half the group had left, three of us were puttering in the parking lot when I saw a peregrine approaching from upriver. Ta dah! This bird has a full crop; none of the songbirds need to worry.
We humans love to be near water, so much so that we build water features where they didn’t exist. We make backyard ponds, scenic ponds, and improve streams.
Garden pond (photo from Wikimedia Commons)Panther Hollow Lake, Schenley Park, March 2024 (photo by Kate St. John)Construction at Phipps Run, Schenley Park, 20 Nov 2021 (photo by Kate St. John)
All along I’ve suspected that these water features, though often beautiful, are not nearly as good as what nature creates. And now we know for sure.
Two studies find that beaver-engineered wetlands attract twice as many hoverflies, nearly 50% more butterflies, and a richer variety of bats compared to human-made ponds or free-flowing streams.
Now that most of the trees are bare(*) we can see nests that were hidden by summer leaves. Among them are those built by hornets, birds, and squirrels.
Papery hornet nests dangle like hanging raindrops or upside-down cones from a sturdy branch.
Squirrel nests — actually called dreys — look like misshapen leaf balls with a few twigs poking out.
A drey is the nest of a tree squirrel, flying squirrel or ringtail possum (in Australia). Dreys are usually built of twigs, dry leaves, and grass, and typically assembled in the forks of a tall tree. They are sometimes referred to as “drey nests” to distinguish them from squirrel “cavity nests” (also termed “dens”).
Squirrels use dreys as nests in spring-summer and shelters in the winter. Before the leaves fall they are busy biting off leafy branches and carrying them up to the winter drey. It takes a lot of effort to keep their shelter warm and waterproof. Brrrr!
In the top photo there are three dreys in three trees and one in the fork of a tree in Schenley Park, below.
Squirrel drey in the crotch of a tree, Schenley, 11 Dec 2016 (photo by Kate St. John)
How can we tell whether it’s a squirrel’s drey or a large bird nest?
Large bird nests, such as the crow nest below, are built of sticks. Squirrels use leaves, especially on the outside.
(*) Most of the trees are bare: For many years I’ve kept track of leaf-off in Schenley Park. Sometimes it’s early, sometimes it’s late. This year most of the trees were bare on or before Friday 14 November 2025. Here’s what the park looked like on that date.
Most of the trees are bare, Schenley Park, 14 Nov 2025 (photo by Kate St. John)
It’s that time of year again when squirrels are suicidal, or so it seems. They watch from the side of the road as your car approaches, dart in front of you, stop in front of you, and then zig zag back and forth in place. If you and the squirrel are both lucky, the squirrel runs out of your way at the last minute.
Squirrels even do this in front of bicycles. In the slow motion part of this video you can see the squirrel pause, zig zag in front of the bike and finally exit left at the last minute.
You would think squirrels would learn that darting in the street leads to death. They do, after all, solve complex problems at your bird feeders every day. But they don’t learn this one.
I think they zig zag in the street because … they’re afraid of cars!
The zig zag behavior is how squirrels evade predators. They react to cars in the same way they handle encounters with animals that want to kill them. Here’s who taught them this maneuver.
Red-tailed hawk watching for prey, November 2008 (photo by Chuck Tague)
When squirrels evolved in North America 36 million years ago, hawks had already been around for more than 90 million years. Squirrels have always been afraid of hawks and have 36 million years of learning how to evade them.
Darting back and forth works best because the hawk (or even a fox) cannot to pinpoint the squirrel’s location to come in for the kill. The closer the predator, the more the squirrels dart.
At the roadside we humans are taught to wait until the car passes, but for a squirrel waiting can turn you into dinner and so can turning your back and running away.
My guess is that squirrels do know that cars are dangerous and use their best evasive tactic. It just happens to be exactly the wrong thing to do.
p.s. It turns out that squirrels think noisy roads are a safer place to be 😮 A recent study in southeast England found that gray squirrels feel safer from predators when they are close to human activity, especially when close to very noisy roads, the noisier the better. See: Animals’ “landscape of fear” gets weird when people enter the equation.
Fur color of two early mammals = Artistic reconstruction of pelage coloration of Arboroharamiya fuscus (CUGB-P1901) and Vilevolodon diplomylos (SDUST-V0010). Science387, 1193-1198(2025). DOI:10.1126/science.ads9734 CREDIT: Chuang Zhao and Ruoshuang Li. (*)
19 October 2025
Mammalian ancestors have been around for 320 to 315 million years, but the first true mammals evolved during the time of the dinosaurs in the Late Triassic. These early mammals were uniformly nocturnal and small, no larger than a house cat, and they were furry. What did they look like? A study in Science in March 2025 examined six fossils species and found they were not as colorful as modern mammals. All of them were dark gray.
Back in 2008 we learned that dinosaurs were colorful. Studies of melanosomes found within their fossils indicated they were not only colorful but sometimes brilliant.
Using the same technique on six Mesozoic mammal fossils, researchers led by Matthew Shawkey compared the fossil melanosomes to those of 116 current (extant) mammals and found that extant mammals have more fur colors while the Mesozoic mammals were all the same color.
The diagram below shows the dark gray color scores compared to extant mammals (** see complete caption at bottom). I have added a pink line to diagram B to point out the difference. Extant mammals on left have a wider range of color (below line) than the fossil mammals (above line).
Fig. 3: Melanosome diversity and pelage coloration: (B) Width variation of melanosomes. Science387, 1193-1198(2025). DOI:10.1126/science.ads9734 CREDIT: Chuang Zhao and Ruoshuang Li. (** see complete caption below)
It’s hard to imagine these ancient mammals until you see an illustration. I have cropped it into two parts. See the complete caption (**) for the entire Fig. 4 below.
At top: Two fossil mammals that resembled flying squirrels. “The green eyes of Arboroharamiya fuscus are an artistic license of the tapetum lucidum, an intraocular reflecting structure that enhances visual sensitivity, indicating nocturnality.“
Below: Three more mammals. (**) see the caption for details.
Fur color of three early mammals = Artistic reconstruction of pelage coloration of Megaconus mammaliaformis (PMOL-AM00007), and Docodontans (SDUST-V0006 & SDUST-V0007). Science387, 1193-1198(2025). DOI:10.1126/science.ads9734 CREDIT: Chuang Zhao and Ruoshuang Li. (*)
Modern mammals are more colorful because melanosomes have changed over millions of years. But the one dark color was just fine for early mammals. They needed nighttime camouflage to hide from many much larger predators.
The full study citation –> Mesozoic mammaliaforms illuminate the origins of pelage coloration. Science387, 1193-1198(2025). DOI:10.1126/science.ads9734
(**) Complete caption for Fig. 4Artistic reconstruction of pelage coloration of five Jurassic mammaliaforms. (Top to bottom) Arboroharamiya fuscus (CUGB-P1901), Vilevolodon diplomylos (SDUST-V0010), Megaconus mammaliaformis (PMOL-AM00007), and Docodontans (SDUST-V0006 & SDUST-V0007). The green eyes of A. fuscus are an artistic license of the tapetum lucidum, an intraocular reflecting structure that enhances visual sensitivity, indicating nocturnality. Eutherian SDUST-V0008 from the Lower Cretaceous is not included in this artistic reconstruction. CREDIT: Chuang Zhao and Ruoshuang Li.
(**) Complete caption for Fig. 3. Melanosome diversity and pelage coloration across extant mammals and Mesozoic mammaliaforms. (A) Scatterplot of individual melanosome measurements from 116 extant mammals and six fossils; dot color shows RGB values derived from spectral curves measured at specific hair locations. Extant hair melanosomes, n = 2615; A. fuscus, n = 760; M. mammaliaformis, n = 103; V. diplomylos, n = 395; docodontan SDUST-V0006, n = 289; docodontan SDUST-V0007, n = 407; eutherian SDUST-V0008, n = 205. (B) Width variation of melanosomes. (C) Length variation of melanosomes. (D) Measured reflectance spectra of selected extant mammals [Vulpes vulpes (orange), Ailurus fulgens (red), Cephalophus dorsalis (brown), Pelomys fallax (darker brown), and Mephitis mephitis (black)] and predicted reflectance curves for six Mesozoic mammaliaforms (browns), highlighting their constrained brown coloration and minimal variation. (E) Detailed view of the predicted reflectance curves for the six Mesozoic mammaliaforms.
Jaguars are rare in Mexico and appeared to be on the brink of extinction when Gerardo Ceballos and his team from the National Alliance for Jaguar Conservation (ANCJ) conducted a nationwide survey in 2010. They were surprised to find 4,100 — four times as many jaguars as they expected. The big cats were Endangered but there was hope.
Jaguars (Panthera onca), native to Central and South America, are the third largest big cat in the world and have a common genetic ancestor with lions and leopards.
Mexico’s small jaguar population is at the northern edge of the range and as close as they come to the U.S. The jaguar’s stronghold is in the South American rainforest and the Pantanal.
After the 2010 census results, ANCJ embarked on a Mexico jaguar conservation campaign to maintain protected areas, reduce jaguar conflict with cattle ranchers, and increase public awareness of jaguars. Then they counted again.
The [2024] census took place over 90 days across 15 states, using 920 motion-capture cameras and involving nearly 50 researchers as well as local community leaders. Researchers looked at an area of 414,000 hectares, making it the largest census for any mammal in Mexico.
In good photos the scientists could avoid double counting because the jaguar’s spots are unique per individual. Their rosette spots have small spots inside them and the pattern and arrangement of rosettes is unique.
Happily the new count totaled 5,326 jaguars, a 30% increase!
Jaguars were found across the country, with the largest number in the Yucatán peninsula region (1,699), followed by the south Pacific area (1,541), north-east and central Mexico (813), the north Pacific (733) and the central Pacific coast (540).
Today I’m taking a break from outdoor stuff to look at an indoor mammal and sleep cycles.
Unlike our society, where humans are expected to have one long sleep period per day(*), cats sleep many times a day in periods lasting 50-113 minutes. They often sleep while we’re awake and wake while we’re asleep. What do they do when we’re not watching?
Familiarity with the robot can breed contempt. This video shows two cats in a dominance face-off — notice their ears! The dominant (black) cat is busy intimidating his fellow cat and wants no interruptions from the robot. With one gesture he sends it away.
Wikipedia explains: Polyphasic sleep is common in many animals, and is believed to be the ancestral sleep state for mammals, although simians (our branch of primates) are monophasic.
