Hey, Cat! Can You Squeeze Through This Opening?

photo from Wikimedia Commons

6 November 2024

How small a hole can a cat squeeze through? CatPusic tested his cat.

embedded video by CatPusic on YouTube

Science:

This hole was a circle, same size all around, but a recent study in Budapest — Cats are (almost) liquid!—Cats selectively rely on body size awareness when negotiating short openings — demonstrated that cats hesitate more when the opening is short than when it is narrow.

Narrow openings don’t bother cats because their free-floating collarbones are attached to muscle, allowing them to flatten vertically.

Short openings are a problem though. Young cats make mistakes.

Cats: We’d had them less than an hour when Sid went in a hole and couldn’t get out – had to break the grill off to let him out. — caption on the photo below by cormac70

Sid was stuck in this hole, Milly watches, July 2008 (photo by cormac70 via Flickr, Creative Commons license)

As cats gain body size awareness they become better at judging short openings.

Poster from the study Cats are (almost) liquid!—Cats selectively rely on body size awareness when negotiating short openings

Though this video is not the iScience experiment, it is very similar.

embedded video by CatPusic on YouTube

Listen to a podcast about this study at Science Magazine. (Note: there is a 1 minute promo before the broadcast begins.)

In The Rut: Deer Pairing Up in Frick Park

8-point buck with doe in Frick Park, 30 Oct 2024 (photo by Charity Kheshgi)

5 November 2024

Last Sunday in Frick Park we were privileged to see an 8-point buck hanging out with a doe. They were obviously a couple and merely gazed at us before returning to their interest in each other. The only thing that really got their attention was an off-lease dog on a trail to the right. Fortunately for the dog, he and his owner went the other way.

The paired stayed close together and the buck licked the doe’s face, ears and estrous. Bright light and shadows make it difficult to see them in this photo so I have brightened the remaining pictures.

8-point buck licks doe’s ears in Frick Park, 30 Oct 2024 (photo by Charity Kheshgi)

Over-bright photos allow you to pick out the deer.

8-point buck licks doe’s face in Frick Park, 30 Oct 2024 (photo by Charity Kheshgi)
8-point buck sniffing doe’s neck in Frick Park, 30 Oct 2024 (photo by Charity Kheshgi)

What we witnessed was the “tending bond” when a buck shadows a doe for 24 to 48 hours, mating with her multiple times and making sure another buck doesn’t interrupt. (We did not stay for their finale.)

Most people never see this because white-tailed deer hide in dense forest during this period but Frick Park has a serious browse line so there is nowhere to hide.

During the 20th century a myth about deer mating practices governed deer management in Pennsylvania. Namely that it was OK to have 1 white-tailed buck for every 7 does because one buck could “service” all of them in the few weeks that all the does were in heat. Surely the males could get it done.

But they couldn’t. By the end of the 20th century PA hunters were routinely harvesting 90% of the bucks before they were two years old because the sex ratio was so skewed that there was not enough time for pairing up.

In 2002 the PA Game Commission changed deer management practices with antler restrictions to protect the young males and increased doe harvest to balance the sex ratio. The combination has given Pennsylvania’s deer the time they need to form a temporary pair bond.

p.s. Watch out for deer crossing the road! Chances way too high that are you’ll hit a deer in PA during the rut in October/November.

Suddenly You’ll See a Lot of Crows

Crows at the roost, 30 December 2023 (photo by Kate St. John)

4 November 2024

Pittsburgh’s winter crow flock is building as more birds from the north join the thousands already here. By the end of December at the Pittsburgh Christmas Bird Count, there will be as many as 20,000 crows on the move at sunset.

This month while the flock is growing, the roosts that were adequate in October are too small, so they move the entire roost or split into several locations. The moving or splitting happens every week, if not more often.

On Halloween they chose a favorite spot in the Hill District overlooking the Allegheny River, but those coming from the southeast had to change course to get to it. Thousands flew over my apartment building just after sunset on 1 November. On 2 November they found a shortcut and took a different route.

Winter crow flock flies to the roost, Pittsburgh, 1 Nov 2024 (video by Kate St. John)

Tonight sunset is during rush hour at 5:12pm and for the first time this fall many people will be outdoors while the crows are on the move. Those who hadn’t noticed the flock before will think the crows suddenly showed up. Nope. Crows have been traveling at sunset all their lives. It’s the people who suddenly showed up.

p.s. Thank you to Sue Faust & Betty Rowland for alerting me to the crows’ whereabouts. It’s always a challenge to find the roost, especially in late December.

Seen Last Week

Frost in the valley at Duck Hollow, 28 Oct 2024 (photo by Kate St. John)

3 November 2024

Last week began with light morning frost but rose to 80°F on Halloween.

The colors were gorgeous at Duck Hollow on Monday …

Fall color and blue sky at Duck Hollow, 28 Oct 2024 (photo by Kate St. John)

… while tendrils of fog chased each other across the river.

Fog tendrils blow slowly across the Monongahela River at Duck Hollow, 28 Oct 2024 (video by Kate St. John)

These wisps were formed at the rivers edge as clear cold air passed over warm water. Sunbeams make this a poor quality video, below, but you can see the wisps starting near shore. (You might also hear a song sparrow chipping in the background.)

Fog forms at Duck Hollow, 28 Oct 2024 (video by Kate St. John)

Slanting light illuminated the trees at Schenley Park.

Fall color and slanting light in Schenley Park, 29 Oct 2024 (photo by Kate St. John)

A leaf-hidden cocoon reminded me why clearing out leaves is bad for insects. This insect will overwinter on a leaf in Frick Park and emerge as — perhaps — a butterfly or month next spring. Or it may become food for a bird this winter. The insect chain is broken where don’t leave the leaves.

Insect cocoon on a leaf at Frick Park, 30 Oct 2024 (photo by Kate St. John)

Making the Sun Set Earlier

Sunset times in Pittsburgh, late 2024 (photo by Kate St. John)

2 November 2024

Spring Forward, Fall Back. Daylight Saving Time ends tonight as our clocks turn back an hour. Tomorrow the sun will set an hour earlier. A lot of us will be grumpy. Some will be depressed.

Most Americans agree that changing the clocks is bad.

Numerous polls have found that most Americans believe that a standard time should be fixed and permanent—as many as 75% favor no longer changing clocks twice per year. One of the most common observations among researchers of varying backgrounds is that the change itself causes most of the negative effects, more so than either standard time or daylight saving time. Researchers have observed numerous ill effects of the annual transitions, including reduced worker productivity, increased heart attacks and strokes, increased medical errors, and increased traffic incidents.

Wikipedia: SP Act Debate

There are places that don’t participate in this dreaded exercise: Arizona, Hawaii, Puerto Rico and other U.S. island territories.

Map of Daylight Saving Time in U.S. from Wikimedia

But there is an area in northeastern Arizona of self-governed indigenous tribal land where part of it uses Daylight Saving Time (DST) and the center does not. The DST area is the Navajo Nation which spans three states and has chosen to use DST. The donut hole is the Hopi Reservation that uses Standard Time. Here’s a closer look.

If you drive from Tusayan, AZ to Tuba City to Ganado to Window Rock in March through October, you will change time zones seven times between Standard Time and DST. (Did I count correctly?) People who have to make that trip will be relieved that everyone is on Standard Time tomorrow.

Changing your clocks: Everything connected to the Internet — mobile phones, etc. — will change automatically at 2:00am Sunday. The rest of the clocks are up to us.

p.s. I wonder what happens to a cellphone on the trip from Tusayan to Window Rock during DST.

Emerging From The Deep

Youghiogheny River dam with lake at normal level (photo from 1993 via Wikimedia Commons)

1 November 2024

In 1944 the US Army Corp of Engineers completed a flood control dam across the Youghiogheny River that created a lake into Maryland. The project included a new bridge for US Route 40 because the Great Crossings Bridge at Somerfield would be submerged and so would the town’s low lying streets and buildings.

map of Youghiogheny River Lake and Recreational Area from USACE via Wikimedia

Normally the lake is full and beautiful. You would never know there was a bridge underneath it.

Beautiful Youghiogheny River Lake (photo from recreation.gov)

But this year a drought in the Youghiogheny watershed has lowered the lake so far that you can walk out on the old Great Crossings Bridge.

video embedded from CBS Pittsburgh on YouTube

This Google Map shows both bridges.

embedded Google Map showing submerged Great Crossings Bridge north of US Route 40

Pittsburgh is not in severe drought so it’s hard to understand how this lake could drop unless you know where the river comes from. The Youghiogheny is a north-flowing river with headwaters in the mountains of West Virginia and Maryland. Notice that the rest of the Monongahela river basin starts in West Virginia as well.

Monongahela River Basin, Youghiogheny highlighted (map from Wikimedia Commons)

The headwaters of both the Youghiogheny and Monongahela have been in drought since early July. At this point the drought is Extreme to Exceptional in western Maryland and West Virginia.

Northeastern US Drought Map, 29 Oct 2024 (map from US Drought Monitor at UNL)

Water levels have dropped in both rivers but the Monongahela cannot afford to get too low because it carries a lot of barge and boat traffic.

Barge moving downstream on the Monongahela River at Duck Hollow, 18 Sep 2023 (photo by John English)

However, there is water upstream to feed the Monongahela. Releases from Youghiogheny River Lake have, in part, kept the Mon navigable.

And so the old bridge emerges from the deep.

p.s. This isn’t the first time the old bridge has been exposed.

There Was Once a Bat on Halloween

Little brown bat in flight, Carondelet Park in Missouri, May 2017 (photo from Wikimedia Commons)

31 October 2024

On Halloween 2008 I came across a small bat roosting on a tree in Schenley Park, described in A Bat on Halloween. Every time I pass the tree, especially on Halloween, I look for a bat but the chances of finding one are slim to none.

Little Brown Bat clinging to an oak in Schenley Park on Halloween 2011 (photo by Kate St. John)

Little brown bats (Myotis lucifugus) used to be one of the most common bats in North America but their population in the Northeast has declined 90% since 2006 because of white nose syndrome (WNS), a disease caused by a European fungus that was accidentally introduced by cave explorers near Albany, NY.

The fungus spreads rapidly. It was confirmed county by county in southwestern PA in 2010, 2011 and 2012 and now it spans the continent. Little brown bats were listed as Endangered by the IUCN in 2021.

Where is WNS? (interactive map from whitenosesyndrome.org)

There are far fewer bats in Pennsylvania this Halloween than there were 16 years ago. It is unlikely that I will ever see a little brown bat in daylight again.

Read more about white nose syndrome at Another Alien Invader and whitenosesyndrome.org.

Older Is Wiser On Migration

White stork in flight, Huelva, Spain (photo from Wikimedia Commons)

30 October 2024

A long term study of white storks (Ciconia ciconia) in Germany and Austria discovered they improve their migration routes year after year as they gain experience. Older is wiser when it comes to migration.

White storks on migration at La Janda, Spain (photo from Wikimedia Commons)

Back in 2013 researchers fitted more than 250 juvenile white storks with tracking devices that followed each bird as it traveled to its wintering and breeding grounds. As the individuals aged they learned shortcuts, used more direct routes, and moved faster in Spring even though it used more energy.

This graph from the PNAS study Learning shapes the development of migratory behavior shows how the storks’ efforts changed over time.

The influence of age on migration duration for white storks (Ciconia ciconia) that were born in southern Germany and tracked continuously from early life onward. — from “Learning shapes the development of migratory behavior” at PNAS

White storks mate for life and set up housekeeping at age 3 or 4. On the graph we can see that older birds — mated adults — were in a rush to get home but young birds with no nest to reclaim spent time dawdling and exploring.

White stork in flight, France (photo from Wikimedia Commons)

With age comes experience and changing priorities.

Older is wiser … and more driven.

Merlin versus Crow: How to Win a Nest

Merlin, eastern US (photo by Wm.H. Majoros via Wikimedia Commons)
Merlin, eastern US (photo by Wm.H. Majoros via Wikimedia Commons)

29 October 2024

Last spring during the nesting season I was so distracted by peregrines that I neglected to check on a merlins’ nest reported in Highland Park. By the time I got over there the young had fledged, the merlins were gone, and a small group of American crows were inspecting the area and commenting on what they found.

Crows are intensely interested in merlin nests because those nests may have been stolen from crows.

Merlins (Falco columbarius) never build a nest. Instead they search for crow or hawk nests, ideally in conifers, and take them over. If the target nest is unoccupied no problem but merlins are feisty and will try for an active crows’ nest by driving off the incubating female crow. If harassing her doesn’t work, they shout at her all day until another predator shows up and forces her to leave.

This often works because merlins are loud and fearless. They’ll drive away anything that irritates them including this raven (a merlin predator not a competitor).

Merlin attack! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)
Merlin attack! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)

However, in southwestern Pennsylvania there are now two species of crows — American crows (Corvus brachyrhynchos) and fish crows (Corvus ossifragus) — and it makes a difference to the merlins’ success.

American crow and fish crow (photos from Wikimedia Commons)

A 2019 study presented at the Wilson Ornithological Society showed that if the merlin nest was successful, chances are the nest had been owned by American crows.

Merlin chicks in nest (photo from Wikimedia Commons)

Behavioral interactions between nest-parasitic Merlins (Falco columbarius) and nest-building Fish Crows (Corvus ossifragus) in a new zone of overlap explains that American crows and merlins have coexisted for millennia so they have forged a working relationship and can reach detente early on. One or the other cuts their losses and nests elsewhere.

Not so with fish crows. Merlins and fish crows are new to each other so they haven’t worked out their differences and continue harassing for a much longer period. Few or none on either side have a successful nest. In the study of 25 fish crow nests in upstate New York, 40% failed due to merlin interference. The study tracked 31 merlin nests and found 66% of those made in fish crow nests did not fledge young.

Autumn and winter are good times for seeing merlins and fish crows in Pittsburgh. It would be interesting to find them interacting in spring and watch what happens.

p.s. Thank you to Don Nixon of PA Merlins for alerting me to this fascinating topic. The paper(*) is by Connor O’H. Loomis and Anne B. Clark (Binghamton University), John Confer (Ithaca College), Kevin J. McGowan (Cornell Lab of Ornithology) but it is behind a pay wall. The fish crow and merlin nesting studies continue beyond 2019 in Ithaca, NY at Cornell Lab of Ornithology.

Yesterday at Duck Hollow

Yesterday’s outing at Duck Hollow, 27 Oct 2024 (photo by Charity Kheshgi)

28 October 2024

Six of us went birding yesterday at Duck Hollow and we didn’t just stand around. Here we are on the move to look in the thickets.

Before the rest of us arrived, Claire Staples captured this image of sky, sun and fog on the Monongahela River at 7:55am.

Sky, sun, fog at Duck Hollow, 27 Oct 2024 (photo by Claire Staples)

As 8:36am the sky cleared a bit. Two contrails make dogleg turns to the north.

Sky and fog at Duck Hollow, 27 October 2024 (photo by Charity Kheshgi)

Our Best Bird skulked in a thicket, of course, but kept making noise. He soon became the most photographed bird of the day: a winter wren in shadow and then in the open.

Winter wren in shadow, Duck Hollow, 27 Oct 224 (photo by Jeff Cieslak)
Winter wren in the open periodically scolding, Duck Hollow, 27 Oct 2024 (photo by Charity Kheshgi)

Duck Hollow’s northern mockingbird is still present and noisy.

Northern mockingbird, Duck Hollow, 27 October 2024 (photo by Charity Kheshgi)

We found a bumper crop of honeysuckle fruit along the Lower Nine Mile Run Trail.

Bush honeysuckle fruit, Lower Nine Mile Run Trail, 27 Oct 2024 (photo by Kate St. John)

Unfortunately …

Invasive honeysuckle berries aren’t strictly bad for birds. They’re an easy food source when birds are in a pinch, but they’re kind of like junk food: Compared to native berries, they have less fat and nutrients that birds need to fuel their long-distance flights. 

Audubon news: Mystery Solved: Invasive Berries to Blame for Turning Flickers’ Feathers Pink

Our “rare” bird of the day was a flock of 16 fish crows vocalizing as they flew. eBird didn’t believe we could find that many but eBird’s “rare” filter doesn’t know about, or cannot pointpoint, the fish crow phenomenon in Pittsburgh’s East End.

See our checklist of 27 species here https://ebird.org/checklist/S200489956 and below.

Duck Hollow, Allegheny, Pennsylvania, US
Oct 27, 2024 8:30 AM – 10:30 AM … 27 species

Canada Goose (Branta canadensis) 26
Mallard (Anas platyrhynchos) 11
Mourning Dove (Zenaida macroura) 3
Killdeer (Charadrius vociferus) 4
Great Blue Heron (Ardea herodias) 2
Belted Kingfisher (Megaceryle alcyon) 2
Red-bellied Woodpecker (Melanerpes carolinus) 1
Downy Woodpecker (Dryobates pubescens) 3
Northern Flicker (Colaptes auratus) 1
Blue Jay (Cyanocitta cristata) 10
American Crow (Corvus brachyrhynchos) 6
Fish Crow (Corvus ossifragus) 16 Flock heading south for the Waterfront shopping center, vocalizing on their way
Carolina Chickadee (Poecile carolinensis) 2
Golden-crowned Kinglet (Regulus satrapa) 1
Winter Wren (Troglodytes hiemalis) 1
Carolina Wren (Thryothorus ludovicianus) 2
European Starling (Sturnus vulgaris) 8
Northern Mockingbird (Mimus polyglottos) 1
American Robin (Turdus migratorius) 60
Cedar Waxwing (Bombycilla cedrorum) 30
House Finch (Haemorhous mexicanus) 13
American Goldfinch (Spinus tristis) 2
Dark-eyed Junco (Junco hyemalis) 4
White-throated Sparrow (Zonotrichia albicollis) 10
Song Sparrow (Melospiza melodia) 6
Yellow-rumped Warbler (Setophaga coronata) 10
Northern Cardinal (Cardinalis cardinalis) 10