When peregrine falcons migrate down the Pacific Coast in autumn they often pause at Canada’s Fraser River Delta to hunt shorebirds. Pacificnorthwestkate (@pnwkate) filmed one working a sandpiper flock at Roberts Bank.
Peregrines on the hunt hope to separate a single bird from the crowd because they cannot catch anything in such a tight flock. When a lone bird can’t keep up it becomes the peregrine’s dinner.
A new study, published this month in Phys.org, looked at the interaction from the peregrines’ perspective and found that the falcons haze the dunlin flocks to keep them moving. Peregrine hunting success improved at the end of those 3-5 hours of continuous flying because the dunlin had to stop for a rest.
The hunting data showed that dunlins were at greatest risk of predation just before and just after high tide, and spent most of the riskiest period flocking. However, there was a sharp increase in kills two hours after high tide, because the dunlins were not flocking despite elevated risk. [They were resting.]
So the dunlin changed their behavior to avoid peregrine predation and the peregrines changed their behavior to wear out the dunlin. Peregrines have more stamina that dunlin.
The region around the Gulf of Naples is very volcanic. There are vents at Solfatara in Pozzuoli where sulfurous steam emerges in an old crater. Pompeii and Vesuvius are across the Gulf.
Nonetheless it’s a lovely place to live by the Mediterranean. Towns, including Pozzuoli, Agnano and Bacoli, dot the crater edges and the flats between them. The area’s population is 500,000.
In September the magma under Campi Flegrei began shifting again and caused more than 1,100 earthquakes in a month, some as strong as 4.0 and 4.2 on the Richter scale. The Guardian reported on 3 October: “The Italian government is planning for a possible mass evacuation of tens of thousands of people who live around the Campi Flegrei supervolcano near Naples.”
Years ago I learned that birds can sense when an earthquake is coming and they take flight before it hits. I suspect that the birds at Campi Flegrei are flying more than usual lately.
Read more about birds and earthquakes in this vintage article from 2016.
How heavy is a puffy white cloud? It depends on how big it is.
According to USGS, an average 1 kilometer by 1 kilometer cumulus cloud weighs about 1.1 billion pounds.
Notice that this calculation uses the metric system for the cloud’s dimensions because it’s so much easier to calculate the weight of a cloud using those units.
When the metric system began in France in the 1790s, the units had Earth measurements as their basis. A kilogram was the mass of water in a 10cm x 10cm x 10cm container (a litre). The cloud answer, above, was calculated in metric and expressed in kilograms, then translated to U.S. customary pounds.
Did you know that we use two measuring systems in the U.S.? Everyday things are described in U.S. customary measures (inches, feet, pounds) but, as described in Wikipedia, science, medicine, electronics, the military, automobile production and repair, and international affairs all use the metric system. Also, most packaged consumer goods in the U.S. have to be labeled in both customary and metric units.
All birds are measured in grams and centimeters. I can tell this common yellowthroat is being banded in the U.S. because there are inches on that ruler. But his tail is about 4.5cm.
Why haven’t we completely adopted the metric system?
It comes down to three things: Time, Money and Congress. The change will cost time and money for U.S. industry, and designating an official measurement system requires an act of Congress. Whenever the subject comes up, lobbyists convince Congress to say “No.”
So for now we use two measuring systems.
p.s. Grams and pounds do not measure the same thing at all. Grams are a measure of mass (a fundamental property of matter). Pounds are a measure of force (the force of gravity on a mass).
If your mass is 68 kilograms, you are … 68 kg in Europe 150 pounds in the U.S., 25 pounds on the Moon and still 68 kg, 0 pounds in outer space and still 68 kg Your mass is 68 kg everywhere you go.
Tricky chipping sparrow, Frick Park, 7 Oct 2023 (photo by Charity Kheshgi)
10 October 2023
Migrating chipping sparrows (Spizella passerina) have just begun to arrive in Pittsburgh and they look different than they did last spring. The adults are fading and the juveniles, which never did match the adults, now resemble other species. We have a category for Confusing Fall Warblers. There ought to be one for Confusing Fall Sparrows.
From mid-March to mid-April chipping sparrows molt rapidly into breeding plumage with a rusty cap, a sharp white swatch above the black eyeline and rusty-orange tones on the wings.
Chipping sparrow in breeding plumage, April 2020 (photo by Lauri Shaffer)
In mid-August the adults being two and a half months of molting into duller non-breeding plumage, looking ragged in September and ending up with the brownish cap and muted facial markings of non-breeding plumage.
Adult chipping sparrow in October 2012 (photo by Steve Gosser)
Meanwhile the juveniles lose the spotted breast they fledged with and gain sharper facial markings. Sometimes they look like clay-colored sparrows which are indeed rare in Pittsburgh.
Let’s compare the young chipping sparrow at Frick Park to an October clay-colored sparrow: chipping on the left, clay-colored on the right below. These small photos are just like the long distance view in the field.
The chipping sparrow has a strong black eyeline that extends all the way to its beak and its face patch has muted edges.
The clay-colored sparrow has no black between its eye and beak but it does have a dark “moustache” outlining the front edge of its face patch.
If you can see the top of the head, the young chipping sparrow may have thin white stripes but the clay-colored has a distinctly wide white crown-stripe.
And just to shake things up, there was a leucistic adult chipping sparrow at Frick last Saturday who looked as if he had been dunked face-first in white paint. His forehead, cheeks and throat were so white that it the camera had a hard time picking up the details.
Leucistic adult chipping sparrow, Frick Park, 7 Oct 2023 (photo by Charity Kheshgi)Leucistic adult chipping sparrow, Frick Park, 7 Oct 2023 (photo by Charity Kheshgi)Leucistic adult chipping sparrow, Frick Park, 7 Oct 2023 (photo by Charity Kheshgi)
Theorectically leucism (lack of pigment) is in his genes so his face will always looks like this no matter what plumage he’s in. He’s the only chipping sparrow I can identify as an individual.
p.s. More confusion: When American tree sparrows arrive later this fall they’ll resemble chipping sparrows in breeding plumage, except that the chipping sparrows will be in non-breeding plumage. Click here and scroll down to see American tree sparrows compared to chipping sparrows at All About Birds.
Birds like the European pied flycatcher (Ficedula hypoleuca) that winter in the tropics and southern hemisphere do not use weather clues to tell them when to fly north in the spring. Instead they cue on changing day length and return at the same time every year. But as Earth’s climate changes, spring comes weeks earlier than it used to and their migration timing is out of sync. Scientists in the Netherlands decided to give a few lucky birds a lift (a Lyft?) to Sweden and it made all the difference.
Pied flycatchers prefer to nest in or near oak trees where their nesting season is timed to correspond with the peak of caterpillar season. Unfortunately, spring is two weeks earlier now in the Netherlands, pied flycatchers arrive too late and have locally experienced a 90% decline.
The old timing of Netherlands’ spring is now found in southern Sweden so scientists at University of Groningen in the Netherlands and Sweden’s Lund University decided to see what would happen to migration and nesting success if a few pied flycatchers were transported (by car!) from the Netherlands to suitable habitat in Sweden.
Anthropocene Magazine reports, “For three springs, starting in 2017, scientists from the University of Groningen in the Netherlands and Sweden’s Lund University caught newly-arrived Dutch female pied flycatchers and drove them by car to a nesting spot 570 kilometers (354 miles) away in southern Sweden that was already home to other pied flycatchers.”
The experiment was wonderfully successful. The Netherlands’ females were in sync with the food supply and were twice as prolific as their Swedish counterparts who were locally out of sync. After spending the winter in Africa the former-Netherlands females returned to Sweden and so did their offspring!
Later the research team proved that migration timing is genetically inherited in European pied flycatchers by taxiing a few eggs laid in the Netherlands to Swedish nests. Those offspring returned to Sweden the following spring on the Netherlands timing.
Taxi service cannot be the answer to out of sync migration but birds are adapting on their own. During the study, banding still continued at Netherlands nests and some of those youngsters were found nesting in Germany, halfway to Sweden. They flew there on their own.
Fall is deer crash season in Pennsylvania. November, October and December, in that order, are the highest months for deer collisions because the animals are on the move in the breeding season.
During the rut, bucks travel an average of 3-6 miles per day searching for and chasing does in heat. Females split from their fawns when they find a mate and the youngsters wander. All age groups are crossing roads more frequently and all of them are distracted.
In Pennsylvania it’s especially important to stay alert because our high deer population increases the odds of a collision. Last month State Farm Insurance reported:
State Farm estimates over 1.8 million auto insurance claims were filed across the industry from July 1, 2022 to June 30, 2023 involving animal collisions. Pennsylvania had the highest number of claims out of all the states, with an estimated 153,397 claims for the same time period.
Nationwide the odds of U.S. drivers hitting an animal are 1 in 127 this year. Drivers in West Virginia held on to the number one spot with the least favorable odds at 1 in 38. Montana (1 in 53), Pennsylvania (1 in 59), Michigan (1 in 60), Wisconsin (1 in 60) round out the top five most likely states to hit an animal while on the road.
In fact PennDOT statistics show that for 2018-2022 Allegheny County leads all Pennsylvania counties in deer-vehicle collisions. Your chance of hitting a deer in Pittsburgh is particularly high.
Statewide the odds of hitting a deer — or a deer hitting you! — are 1 in 59 and probably higher in Pittsburgh. This means that each one of us knows someone who will hit a deer in the year ahead. It might be us.
Stay alert behind the wheel, especially at dawn and dusk. Watch out!
Hunter harvest is the primary cause of white-tailed deer mortality in rural landscapes, while deer in suburban landscapes are more likely to die in deer-vehicle collisions. [p.10]
Managing a deer herd via vehicle collisions is both inhumane and costly for community residents. [p.30]
Honeybee on asters, Schenley Park, 28 Sept 2023 (photo by Kate St. John)
7 October 2023
The best photos from this week have been published already (Yesterday at Hays Woods Bird Banding) so I’m reaching back to late September for a few of things I’ve seen.
Bees of all kinds are attracted to deep purple asters beside the Westinghouse Memorial pond in Schenley Park. The honeybee, above, is hard to see near the flower’s orange center.
At Duck Hollow, yellow jewelweed still has flowers as well as fat seed pods. Try to pull one of the pods from the stem and see what happens.
Yellow jewelweed flower and seeds, Duck Hollow, 26 Sept 2023 (photo by Kate St. John)
On 28 September I explored the slag heap flats near Swisshelm Park where (I think) solar arrays will be installed. Because the slag is porous the flats are a dry grass/scrub land where this shrub would have done well except that it’s been over-browsed by too many deer. It looks like bonsai.
Deer damage at the future site of solar flats, NMR Valley, 28 Sept 2023 (photo by Kate St. John)
Deer overpopulation is also evident by the browse line at the edge of the flats.
Browse line at the edge of the future solar flats,NMR Valley, 28 Sept 2023 (photo by Kate St. John)
On 26 September at Duck Hollow I encountered an optical illusion where Nine Mile Run empties into the Monongahela River. It looks as if this downed, waterlogged tree is damming the creek and that the water is lower on the downriver side of it. This illusion seems to be caused by the smooth water surface on one side of the log.
Optical illusion: the log is damming Nine Mile Run, 26 Sept 2023 (photo by Kate St. John)
We found a tiny red centipede crossing the trail at Frick Park on 30 September …
Tiny red centipede, Frick Park, 30 Sept 2023 (photo by Kate St. John)
… and a puffball mushroom outside the Dog Park.
Puffball mushroom, Frick Park, 30 Sept 2023 (photo by Kate St. John)
On 27 September hundreds, if not thousands, of crows gathered at dusk near Neville Street in Shadyside before flying to the roost. I thought this would happen again the next day but they changed their plan and have not come this close again.
Hundreds of crows take off from a roof on Neville Street, 27 Sept 2023 (photo by Kate St. John)
Sometimes sunrise is the most beautiful part of the day.
Sunrise at Neville Street, 28 Sept 2023 (photo by Kate St. John)
These photos don’t give the impression that it’s been abnormally dry, but precipitation in Pittsburgh is down 6″ for the year. Almost 2″ of that deficit occurred in September. The Fall Color Prediction says our leaf color-change is later than usual.
Fallen leaves in Schenley Park, Nov 2016 (photo by Kate St. John)
6 October 2023
In October we see woolly bear caterpillars (Pyrrharctia isabella) out in the open crossing the trails. Woolly bears overwinter as caterpillars so this month they’re busy looking for the perfect place to spend the winter in leaf litter, under bark, or beneath a fallen log.
Woolly bear, Isabella Tiger Moth caterpillar, 3 Oct 2018 (photo by Kate St. John)
Leaf litter is key winter habitat for a lot of insects including springtails, millipedes, earthworms, butterflies and moths.
Millipede(*) Hays Woods, Sept 2023 (photo by Kate St. John)
If you’ve been thinking about “wilding” your yard — even just a little bit — now is a great time to start. Leave the leaves. You don’t have to leave it messy. Here’s advice on what to do.
Leaving the leaves and other plant debris doesn’t have to mean sacrificing your yard to the wilderness. The leaves don’t need to be left exactly where they fall. You can rake them into garden beds, around tree bases, or into other designated areas. Too many leaves can kill grass, but in soil they can suppress weeds, retain moisture, and boost nutrition.
Avoid shredding leaves with a mower. Raking or blowing are alternatives that will keep leaves whole for the best cover and protect the insects and eggs already living there.
If you decide you need to clean up the leaves and debris in spring, make sure you wait until late in the season so as not to destroy all the life you’ve worked to protect.
Take a break this weekend. Don’t bag those leaves! Just push them aside for wildlife. 🙂
(photos by Kate St. John and from Wikimedia Commons)
(*) p.s. The millipede was easy to photograph because it was dead, probably the victim of a parasitic fungus that prompts the millipede to climb high on a twig before it dies. I wrote down the name of the fungus when I took the picture but cannot read my writing. Perhaps it’s Anthrophaga myriapodia.
The blackpoll’s transoceanic path was proven in a 2015 study by Bill DeLuca and the Vermont Center for Ecostudies. VCE writes:
Bill DeLuca (Northeast Climate Science Center) and VCE solved this great modern-day avian mystery. Using light-level geolocators attached to Blackpoll Warblers in Vermont and Nova Scotia, DeLuca and colleagues documented the longest distance non-stop overwater flights ever recorded for a migratory songbird. During October, Blackpoll Warblers initiate a ~3-day non-stop transoceanic flight of ~2500 km from the north Atlantic Coast to Hispaniola and Puerto Rico. Radar data show migrating songbirds fly at 2,600 to 20,000 feet while making this journey. After a few weeks, they fly onto Columbia or Venezuela where they overwinter. Their spring migration route takes them over Cuba to Florida, where they journey up the eastern US seaboard to reach their breeding grounds in late May.
Of course I wondered if blackpoll warblers sleep in flight during their 3 day transoceanic trip, but we won’t find out any time soon. Blackpolls are way too small to wear the sleep monitoring gear used on the great frigatebird.
(photo from Wikimedia Commons, maps from eBird Weekly Abundance; click on the captions to see the originals)
