I’ve seen a lot of ravens in the past two weeks — 11 in Minnesota, two as we landed at Pittsburgh airport, and one over Aspinwall on Tuesday. When I found Vance Crofoot’s 3-minute video explaining raven territories I was fascinated.
Immature ravens spend 3 to 4 years in large flocks of young ravens. On reaching adulthood, ravens pick a mate and go off to claim a territory.
Adult pairs display their territorial boundary by flying along the border.
Ravens know their neighbors and will sometimes fly with them along the mutual border.
Ravens help their neighbors drive out predatory threats.
Other ravens are not allowed to land in an adult pair’s territory. If they do they are challenged.
When a pair has chicks they aggressively drive out predators.
Once the chicks can fly, neighboring families meet up for “play dates” with their kids.
Youngsters also can bring friends home to play with.
Juvenile ravens stay with their parents for about 7 months. At the end of that time their parents aggressively drive them out of the territory.
The first comment on the video points out how different ravens are from crows!
Very informative! It’s interesting that the intergenerational behaviour is different from crows whose juveniles hang around longer and actively assist their parents in raising the next chicks and fledglings. The ravens’ cooperative behaviours are very well adapted to their needs and types of threats.
Owls have excellent eyesight but they see the world differently than we do.
When we look straight ahead (fixation point below) our peripheral vision allows us to faintly see our hand waving near our ear — a 200-220° field of view.
Since their eyes are always facing forward, they have to move their heads or their bodies to see anything outside their narrow field of view. Moving their bodies would alert their prey, so owls have evolved to move their heads as far back as they need to see — up to 270°.
Owls have 14 neck bones for greater flexibility. We have only 7 neck bones
Great horned owlet about to be delivered to temporary nest, Schenley Park 11 March 2025 (photo by Dana Nesiti)
12 March 2025
Almost two weeks ago this 6-week-old great horned owlet fell 100 feet from her nest on the Panther Hollow Bridge and was rescued and taken to Tamarack Wildlife Center. Tamarack determined her injuries were so minor that she was ready for release quite soon. But where to take her? Her birth-nest is inaccessible.
Panther Hollow Bridge, Schenley Park, with owls’ nest indicated (photo by Kate St. John)
She needed to be in a foster family with siblings her age but she is older than other known nestlings in western PA. (Her parents nest really early.) In the end the best choice was to return her to her parents by placing her in a temporary nest near the bridge.
Yesterday she went home with help from Tamarack Wildlife Center, City of Pittsburgh Forestry and Pittsburgh Park Rangers. Her adventure is documented in these photos by Dana Nesiti.
First, her temporary nest was placed 20-30 feet up in a tree within sight and sound of her parents. Then George DeSavage of City Forestry received her from Tamarack staff.
The handoff, great horned owlet on his way to the temporary nest in Schenley, 11 March 2025 (photo by Dana Nesiti)
As a parting shot she bite the gloved finger of her Tamarack handler. Fortunately those gloves are very thick.
Owlet bites a finger during the handoff, fortunately in a stout glove! Schenley Park, 11 March 2025 (photo by Dana Nesiti)
Then she rode in the bucket truck to her temporary nest …
Owlet on his way to the temporary nest via bucket truck, Schenley Park, 11 March 2025 (photo by Dana Nesiti)
… and settled in.
Great horned owlet in his temporary nest, Schenley Park, 11 March 2025 (photo by Dana Nesiti)
She is just the right age to begin “branching” — walking off the nest — so her parents will not be surprised to hear her away from the birth-nest. When she wakes up hungry she will make begging calls like this and her parents will bring her food.
Tamarack explains:
Over the next 3-4 weeks, she will practice perching, hopping, flapping and short flights before being fully able to fly at around age 9 weeks.
Great Horned Owls spend more time with their young than any other owl species in Pennsylvania. Six months or more are spent supporting their young and teaching them hunting skills, before encouraging their young to disperse in the fall.
A new study published last week in the journal Science analyzed butterfly surveys from 2000 to 2020 to determine the population status of each species in the continental U.S. The results were sobering.
Total butterfly abundance (all individuals of all species) decreased across the contiguous US at a rate of 1.3% annually, for a cumulative 22% decline in overall abundance between 2000 and 2020.
The only region of the continental US that didn’t suffer was the Pacific Northwest where the total population remained stable and the highly irruptive California tortoiseshell (Nymphalis californica) surged on and off as expected.
The study found that declines were common and increases rare.
Over our two-decade study period, 33% of individual butterfly species (114 of 342) showed significantly declining trends in abundance. Conversely, only 3% of species increased.
For instance, the West Virginia white (Pieris virginiensis), above, declined each year by nearly 20%, in part because they are fooled into laying eggs on invasive garlic mustard that kills their caterpillars. By now 98% of them are gone.
And in southern Texas and south Florida the Soldier butterfly (Danaus erisemus), a relative of the monarch, declined about 15% per year, which means about 96% of them gone.
Did you know that peregrines touch beaks during courtship?
As egg laying time approaches, Pitt peregrines Ecco and Carla have been courting four and five times a day and engaging in long bowing sessions. Yesterday’s courtship included several touching moments beak-to-beak (shown below without distracting audio).
After Ecco left, Carla stayed at the nest for more than an hour stretching, snoozing, sunning, puttering , and preening. This is a good sign that she’s getting into breeding condition.
Every autumn barnacle geese (Branta leucopsis) leave their arctic breeding grounds and migrate to Europe. In 2021-2022, those wintering at Solway Firth, UK(*) became infected with highly pathogenic avian influenza (HPAI) H5N1 and 31% of them died. Even though their population had been devastated, they recovered to full strength in just two years. This can give us hope for North American birds hit hard by bird flu.
Wild barnacle geese breed in Greenland, Svalbard and Siberia yet each population has its favorite wintering site as shown on the map. Counts on the wintering grounds are directly tied to one breeding location.
When bird flu hit Solway Firth in the winter of 2021-2022 researchers began a two+ year study to measure the demographic impact of the major HPAI outbreak on barnacle geese. During the outbreak they carefully counted dead goose carcasses and, thanks to fencing, were able to extrapolate for predation.
By February 2022 the barnacle goose population had dipped precipitously, but in the two years that followed the number of juveniles increased even faster. High birth rates on the breeding grounds quickly made up for the loss of adults.
The large impact of HPAI-related mortality on the Solway Barnacle Goose population was rapidly recovered, probably through a combination of the widespread development of natural immunity and high levels of breeding success in the years following the outbreak.
In Pennsylvania, snow geese have been hard hit with wild bird flu. It will be interesting to watch how their winter population fluctuates in the eastern U.S. in the years ahead.
p.s. We don’t have barnacle geese in the U.S. Here’s look like.
Barnacle geese (center of photo) look unique but are similar in size to their nearest relative the cackling goose.
Size comparison! Though cackling geese look like Canada geese they are much smaller. Thus barnacle geese are smaller than Canada geese we see in Pittsburgh.
Golderod in winter, Beechwood Farms, 3 March 2025 (photo by Kate St. John)
8 March 2025
During this week’s brief and gorgeous warm weather I thought it was spring and took photos of interesting plants at Beechwood Farms. Back home I see that they are wintry weeds and trees with only a hint of what is to come.
Goldenrod, above, has not yet released its fluffy seeds to the wind.
I was fascinated by the yellow bark on these maple-family twigs. Is it box elder …?
Whose bud is this? Beechwood farms on 3 March 2025 (photo by Kate St. John)
Yes. The yellow bark threw me off but the opposite buds and green bark on older branches are both traits of box elder (Acer negundo).
What species is this small tree? Beechwood Farms on 3 March 2025 (photo by Kate St. John)
The mystery leaves, below, required my plant identification tool but the answer was unsatisfying and probably wrong. Dame’s rocket (Hesperis matronalis)? I doubt Beechwood would have left such an invasive plant in place.
New leaves at Beechwood Farms on 3 March 2025 (photo by Kate St. John)
However, the tool pointed me to a video about eating Dame’s rocket (Hesperis matronalis) in the spring. Great idea! This plant is invasive. (In the video it is called wild phlox. Maybe a Canadian common name for it.)
Great horned owl nestling showing new wings, 4 Mar 2025 (photo by Jim McCollum)
7 March 2025
On Tuesday 4 March Jim McCollum visited Schenley Park to see the great horned owls’ nest. While there he was lucky to see a nestling stand up and stretch. Look who has wings!
Great horned owl nestling & mother in Schenley, 4 March 2025 (photo by Jim McCollum)
Great horned owl family in Schenley Park, 4 March 2025 (photo by Jim McCollum)
Great horned owl nestling in Schenley Park opens his new wings, 4 March 2025 (photo by Jim McCollum)
Great horned owls in Schenley Park, 4 March 2025 (photos by Jim McCollum)
These wings are not fully developed yet but they are looking good and will be further along today than they were three days ago.
When will the Schenley owlets fly?
Here is my best guess at when the nestlings will fly from the Schenley Park bridge nest.
Based on their appearance and behavior I think the first egg hatched around 5 February and the second about two days later. Approximate hatch dates = 5-7 Feb. [Update from Tamarack: Hatching was approx 28-30 January.]
Great horned owl nestlings walk off the nest and start “branching” at 5-6 weeks = approximately 12-21 March.
Branching youngsters fly away from the nest — “fledging” — at 9-10 weeks = early April. I am not sure of this estimate. It may be sooner (late March) though I doubt it will be later in April.
Peregrine at the Tarentum Bridge, 4 Feb 2025 (photo by Dave Brooke)
6 March 2025
There’s a lot of peregrine news in southwestern Pennsylvania right now as mated pairs prepare to nest. Our earliest couple is already on eggs at the Tarentum Bridge.
Tarentum Bridge, Allegheny River:
On Tuesday 4 March Dave Brooke saw the gray lump of a peregrine’s head laying low in the nestbox. This position usually indicates incubation is in progress, particularly if the bird does not move around.
Female peregrine apparently incubating at the Tarentum Bridge, 4 March 2025 (photo by Dave Brooke)
Last year the Tarentum Bridge female laid eggs around February 21st so it is very likely she’s on eggs right now at this location:
Tarentum Bridge nestbox (photo by Amber Van Strien)
Cathedral of Learning, Univ of Pittsburgh:
Ecco and Carla are on the National Aviary falconcam several times a day as they court and prepare their nest. Yesterday their third courtship session lasted five minutes, then Carla puttered at the nest for an additional eight minutes. The length of both activities indicates how close they are to nesting.
This 2+ minute video is just a small part of their late afternoon courtship session. The fade-to-black transition marks the moment when Carla begins puttering.
On 4 March Adam Knoerzer captured proof that the peregrines at East Liberty Presbyterian Church are planning to nest. Look closely and you can see the male fly in and mate with the female on the steeple.
East Liberty Presby peregrines mating, 4 March 2025 (video by Adam Knoerzer)
Sewickley Bridge, Ohio River:
Happy news at the Sewickley Bridge! Yesterday, 5 March, I had to run an errand in Sewickley so I stopped by the Chestnut Street boat ramp (in the rain!), saw a peregrine at the nestbox and told Jeff Cieslak. After the rain ended Jeff found both peregrines at home, one in the nestbox and one on the pier near the nav light (yellow arrows).
Woo Hoo! Thank you, Jeff, for requesting this nestbox last year and thanks to PennDOT for installing it.
Peregrine in nestbox and one on the pier at Sewickley Bridge, 5 March 2025 (photo by Jeff Cieslak)
Spruce Run Bridge, Ohio River:
Female peregrine at Spruce Run, 11 Feb 2025 (photo by Jeff Cieslak)
Jeff Cieslak checked for peregrines along the Ohio River throughout February. He found the female at her Spruce Run home on the 11th and what seems to be both of them on nearby Neville Island on the 25th.
One, maybe two, peregrines on a Neville Island smokestack in the Spruce Run territory, 25 Feb 2025 (photo by Jeff Cieslak)
Eckert Street / McKees Rocks / Brunot Island, Ohio River:
The “Eckert Street peregrines,” who didn’t nest at Eckert Street last year, have so many places they could choose to nest that they are hard to keep track of. Last month Jeff Cieslak found one hanging out on the Alcosan smokestack and the other on a nearby power tower.
Peregrine on the Alcosan smokestack, Eckert Street territory, 11 Feb 2025 (photo by Jeff Cieslak)
Jeff’s photo indicates the male is in immature plumage. Though young, there are records of male peregrines breeding at this age so we’ll have to wait and see what happens.
Male peregrine in the Eckert Street/McKees Rock territory appears to be immature, 11 Feb 2025 (photo by Jeff Cieslak)
Westinghouse Bridge, Turtle Creek near Monongahela River:
On 25 February Dana Nesiti found both peregrines at home at the Westinghouse Bridge. He suspects they courted near the scrape while he was there, though he couldn’t see tit.
Female peregrine at the Westinghouse Bridge, 25 Feb 2025 (photo by Dana Nesiti)Male peregrine at the Westinghouse Bridge, 25 Feb 2025 (photo by Dana Nesiti)
PEREGRINE SUMMARY FOR SOUTHWEST PA: All the potential sites and latest sightings are listed below. Help fill in the blanks by visiting one of these locations. Leave a comment if you need my help in finding the site.
Woodland crocuses blooming in the lawn on Neville Street, 4 March 2025 (photo by Kate St. John)
5 March 2025
The crocuses are blooming!
But of course they are. In yesterday’s sunny and unseasonably warm 67°F the woodland crocuses (Crocus tommasinianus) on Neville Street were in full bloom. I say “were” because today’s rain, clouds and wind will probably keep them closed.
The crocuses dotted the lawn, above, and opened their petals to the sun.
Woodland crocus blooming in the lawn on Neville Street, 4 March 2025 (photo by Kate St. John)
Honeybees came to take a sip.
Bee visits blooming crocuses in the lawn on Neville Street, 4 March 2025 (photo by Kate St. John)
Now that they’ve opened, how does this year’s crocus bloom date compare to those in the past? Is it later than usual because we had such a cold winter?
Surprisingly, this year is on the early end of the spectrum, based on my record of Crocus First-Bloom Dates in Pittsburgh’s East End since 2009.
I don’t have a crocus record but the date was probably March 7, 2016 based on temperature data, this post about coltsfoot, and feedback from Supriya in Squirrel Hill.
Plotted on the calendar it’s easy to see that the dates cluster and the outliers are early, not late. Repeated dates are circled twice. Interestingly, the dates in February become earlier each time they occur.
