1 December 2023
What frightens a mountain lion (Puma concolor) enough to make it run away?
This video from a camera trap in Whatcom County, Washington provides the answer.
(credits are in the captions)
What Makes a Mountain Lion Run Away?
All posts by Kate St. John
They Want to Cull Barred Owls Again
30 November 2023
Sometimes history repeats itself.
In 2013 US Fish & Wildlife proposed an experiment: Kill 3,600 barred owls (Strix varia) in the Pacific Northwest to keep them away from their close relative, the northern spotted owl (Strix occidentalis). Barred owls had spent 100 years expanding westward to the Pacific coast where they became more successful than their habitat-constrained spotted cousins and even interbred with them. Though barred owls are native to North America and moved west on their own, USFW dubbed them “invasive” and proposed killing them wherever found near spotted owls.
Nationwide comments on the culling proposal were overwhelmingly negative but local comments were in favor. The experiment went forward and barred owls were killed according to plan. The final paper describes barred owl “removal”.
Barred owls detected in treatment areas were removed using 12-gauge shotguns and well-established field protocols (20, 22, 23). A total of 2,485 barred owls were removed from treatment segments of five different study areas during the experiment (Table 1). The mean number of barred owls removed per year was highly variable among study areas, ranging from a low of 15.8 barred owls per year in Green Diamond (GDR), to a high of 251.5 barred owls per year in the Oregon Coast Range (COA).
— FWS.GOV Study Results: Invader removal triggers competitive release in a
threatened avian predator
The five locations where removal occurred, called “treatment” areas, and the number of barred owls killed are shown in the screenshot of Table 1.
Interestingly at two of the five study sites — Hoopa-Willow Creek and Green Diamond, California — the killing of 494 barred owls made little to no difference for the spotted owls. Click here for the graph that shows this.
However, USFW declared the experiment a success and recently drafted a new “Barred Owl Management” proposal to continue killing barred owls and expand the project further in California. The draft is currently in its 60-day public comment period: November 17, 2023 – January 16, 2024 during which we are free to express our opinion.
Read about the proposal and download relevant documents at Fish and Wildlife Service seeks public comment on draft strategy to manage invasive barred owls. Click here to submit a comment online or paper-mail your comments to the address below. The comment period ends on 16 Jan 2024.
Public Comments Processing; Attn: Docket No. FWS-R1-ES-2022-0074 U.S. Fish and Wildlife Service Headquarters, MS: PRB/3W 5275 Leesburg Pike Falls Church, VA 22041–380
p.s. Here’s what I thought of this idea 10 years ago. I haven’t changed my mind.
Shagbark Hickory Nuts
29 November 2023
The Nutty Series: Shagbark hickory
Last month shagbark hickories (Carya ovata) put on a show in Pittsburgh’s parks with bright yellow leaves and fallen nuts.
The thick green husks began to turn brown immediately and peel off in quarter-moon sections. This piece of husk sat indoors for more than a month before I took a photo of its interior. The dark brown exterior is visible at the bottom edge.
If a nut lasts through the winter its husk looks quite worn out by March. This one was probably uneaten for a good reason.
Shagbark nutshells are slightly oval with a remnant stem and four ribs. When I cracked open the nut I collected, it was a dud. Maybe an insect got to it. This Wikimedia photo of a sawed nut shows the meat.
Though shagbark hickory nuts taste good and can substitute for pecans, shagbarks are not cultivated because …
They are unsuitable to commercial or orchard production due to the long time it takes for a tree to produce sizable crops and unpredictable output from year to year. Shagbark hickories can grow to enormous sizes but are unreliable bearers.
C. ovata begins producing seeds at about 10 years of age, but large quantities are not produced until 40 years and will continue for at least 100. Nut production is erratic, with good crops every 3 to 5 years, in between which few or none appear and the entire crop may be lost to animal predation.
— Wikipedia Shagbark Hickory account
Interestingly, shagbarks (Carya ovata) and pecans (Carya illinoensis) can hybridize in the wild though the hybrids usually don’t produce nuts.
Shagbark hickories are easy to identify by their shaggy bark. Just look up and you’ll see it peeling from the trunk. Young trees can fool you, though, because they have smooth bark (click here to see young bark).
Shagbarks are one of the first native trees to leaf out so their sap runs early in the spring. Yellow-bellied sapsuckers (Sphyrapicus varius) take advantage of this and drill the trees as they migrate north. The birds move sideways around the trunk as they drill in a ring around the tree. The trees heal the wounds by producing callus tissue that grows outward, almost like lips. These attract the the sapsuckers who then drill the same rings year after year.
(credits are in the captions)
Kissing Trees
28 November 2023
If you’ve spent a lot of time in the woods chance are you’ve see trees kissing. The fusion of their trunks in what looks like a kiss is called inosculation from the Latin word for kiss.
University of New Hampshire explains how it occurs:
Inosculation happens when the friction between two trees causes the outer bark of each tree to scrape off at the point of contact. The trees respond by producing callus tissue that grows outward, thereby increasing the pressure between the two trees. This pressure, along with the adhesive nature of sap or pitch that exudes from the wounds, reduces the amount of movement at the point of contact. The cambia layers from the two trees come in contact and the vascular tissues become connected, allowing for the exchange of nutrients and water.
— UNH: Inosculation: Making Connections in the Woods
Though I’ve seen fused trees several times, I have only one photo of a pair “kissing,” fused twice at Raccoon Creek State Park in February 2015. The date is notable because that hike is also the last time I saw a long-eared owl.
An extreme case tweeted by Science girl @gunsnrosesgirl3 reminded me of the phenomenon. The smaller tree on the left does not touch the ground and is completely sustained by the larger one that’s holding it up. The embedded tweet below does not show that the smaller tree is cut off so click here to see a larger photo.
Some species are more likely to “fuse “kiss” because their bark is thin. Check out this list of likely suspects at Wikipedia.
(credits are in the captions)
El Niño Snows in DC But Not Pittsburgh
27 November 2023
Last week a friend remarked on the wide variety of winter forecasts being touted for Pittsburgh from “Swamped With Snow” to “No Skis in Our Forecast.” How could the predictions be so different? I think it’s the Beltway effect.
Right now the world is in an El Niño year of warm sea surface temperatures in the central and eastern Pacific at the equator and along the coasts of Ecuador and Peru.
According to Wikipedia, this warming causes a shift in the atmospheric circulation with rainfall becoming reduced over Indonesia, India and northern Australia, while rainfall and tropical cyclone formation increases over the tropical Pacific Ocean. El Niño seriously affects South American weather and ripples out to North America as well. The U.S. seasonal outlook, Dec 2023 to Feb 2024, shows higher temperatures in the north and wetter weather in the south this winter.
Of course this affects snowfall. El Niño’s winter history in 1959-2023 shows more snow in some places (blue color) and a lot less in others (brown color). Interestingly, Pittsburgh is in the Less Snow category while Washington, DC has More Snow than usual.
News organizations have a big presence in the DC Beltway area and write stories for the region. Some weather stories originate there and cross the Appalachians but when the news gets to Pittsburgh it might not apply to us. The typical example is when 2 feet of snow are forecast for D.C. and hardly any falls here. I think of this as the (DC) Beltway news effect.
So when we hear dire predictions for Pittsburgh’s winter this year I plan to wait rather then worry. My guess is that we’re likely to have rain.
I sure hope the temperature doesn’t hover near freezing when it rains. Fingers crossed that we’ll be fine.
Read more about snow and El Niño at NOAA’s S(no)w pain, S(no)w gain: How does El Niño affect snowfall over North America?
African Penguins Use Dots to Recognize Mates
26 November 2023
We humans recognize each other by face and can sometimes recognize individuals in other species as well. For instance, African penguins (Spheniscus demersus) have unique patterns of dots on their chests that zookeepers use to tell them apart. Psychologist Luigi Baciadonna wondered if the dots functioned the same way for the penguins themselves so he ran an experiment at Zoomarine Italia in Rome.
In the experiment individual penguins were herded into a small corral with life-size portraits of two group members, at least one of which was his/her mate. African penguins like to hang out near their mates so if the visiting bird stared at the mate’s portrait and gravitated toward it, he/she was recognizing the mate. The experiment had three variations:
Test #1: Accurate photos: one of the mate, one of another member of the colony. Result: In this video of Test#1 a male penguin, Gerry, is presented with an image of his partner, Fiorella, on the left and one of group member Chicco on the right. Notice what he does.
Test 2: Two photos of the mate: one accurate, one with dots digitally removed. Result: The birds spent more time looking at the mate photo with dots.
Test 3: Dots digitally removed from both photos: mate and another member of the group. Result: The birds no longer seemed to recognize their mate. There was no difference in how long they gazed at the mysteriously spotless portraits.
Quiz! Now that I know African penguins have unique chest dots I discovered that the penguin pictured below is also in a photo above. Which one is he?
Visit the National Aviary in Pittsburgh to check out the African penguins’ dotted chests at Penguin Point.
Read more about the study at Science Direct: African penguins utilize their ventral dot patterns for individual recognition
(credits are in the captions)
A Yellow Carpet
25 November 2023
On Wednesday I found a yellow carpet on Elmer Street. Ginkgo trees were shedding their leaves all at once.
The ground was gorgeous and so were the branches.
Some trees were already bare. Some were yet to come.
But there were hazards beneath this beauty. Ginkgos are dioecious (with separate sexes) and the females produce fruits that smell like vomit. Landscapers try to plant only male trees but there was a female in this mix.
I didn’t pay attention until I stepped on a fruit and felt it pop beneath my heel. Yuck! The stinky flesh stuck in the treads of my shoe so I searched for a puddle to stomp in, too preoccupied to take a picture of the fruits. These are from Wikimedia.
Ginkgos were planted along Pittsburgh’s street during the Smoky City era because they’re one of the few trees that do well in polluted air. We can expect them continue for 100s of years.
In 2020, a study in China of ginkgo trees up to 667 years old showed little effects of aging, finding that the trees continued to grow with age and displayed no genetic evidence of senescence, and continued to make phytochemicals(*) indefinitely.
— Wikipedia: Ginkgo biloba account
(*) Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. Gingkos have great immune systems even when more than 600 years old.
Deer Seasons Switch This Weekend
24 November 2023
Deer hunting seasons are changing this weekend in Pennsylvania. Archery season will pause tomorrow (25 Nov) until the day after Christmas (26 Dec) because Deer Rifle Season begins on Saturday 25 November and runs through 9 December including THIS SUNDAY 26 November.
CORRECTION! (Thanks to Noelle’s comment) The archery hunt in Frick and Riverview Parks does take a pause in December but those dates match Allegheny County’s Archery season, not the statewide dates listed above. Engage Pittsburgh lists the 2023 archery dates in the City of Pittsburgh as: Saturday, September 30 – Saturday, December 9* and Tuesday, December 26 – Saturday, January 27 (2024)* *Excluding Sundays.
Meanwhile, the City’s deer are wise to what’s going on and have left Frick Park to browse their way through the neighborhoods. The pair pictured above visited a Squirrel Hill polling place on Election Day.
Deer hunting will be particularly intense in the countryside this weekend so wear orange if you go for a walk in the woods!
The PA Game Commission’s 2023-2024 Hunting and Trapping Pocket Guide lists the seasons in a nutshell. I’ve highlighted the remaining deer hunting days. Pink+arrow indicates Archery days in the City of Pittsburgh. We are in WMU 2B.
Deer Hunting Dates in PA, 25 November 2023 – 27 January 2024
WMUs for the extended hunts are circled below.
(credits are in the captions)
Turkey Day
23 November 2023
Wild turkeys (Meleagris gallopavo) are thriving in Pittsburgh’s suburbs. This flock of 14 feels right at home in a Kathy Saunders’ backyard.
Meanwhile, where have all the city turkeys gone? A decade ago they were easy to find in Schenley Park and Oakland but I haven’t seen one here in three years. This vintage article describes an impromptu Turkey Day at WQED when six came for a visit in November 2011.
Happy Thanksgiving!
(credits are in the captions)
Black Walnuts
22 November 2023
The Nutty Series: Black walnut
Black walnut trees (Julgans nigra) are common in the Pittsburgh area. Their nuts are always ready to eat in time for the holidays.
In September the fruit was still on the trees while we searched for fall warblers among the leaves.
By the end of October the fruit had fallen and started to look bruised. Eventually the husks turned black.
But most black walnuts aren’t abandoned that long. Squirrels gather them for winter food and eat a few along the way.
Squirrels know that they have to open the shell on both sides to get all of the nut meat.
The meat does not come out easily! It usually breaks into small pieces on the way out and is never the perfect shape of grocery store walnuts.
The ones we buy in the grocery store that are grown in California are English walnuts (Juglans regia) which would not be possible without the life-giving participation of black walnut trees (Julgans nigra).
Non-native English walnuts are susceptible to root diseases in California so walnut farmers plant native black walnut trees to start the orchard. When the black walnuts are a year old with strong roots and vigorous base they are chopped off and an English walnut shoot is grafted to the stump.
All the trees in the orchard below show the wider stump base (highlighted in yellow) that ends at the graft point. Above the graft English walnuts produce their own delicious nuts which are harvested after they fall by sweeping and vacuuming from the ground. FLORY harvesting equipment is pictured below.
Black walnut trees can be identified in winter as a bare tree standing alone with twigs that have alternate (not opposite) small buds above large leaf scars.
Black walnut trees stand alone because …
Like other walnuts, the roots, inner bark, nut husks, and leaves [of Julgans nigra] contain a nontoxic chemical called hydrojuglone; when exposed to air or soil compounds it is oxidized into juglone that is biologically active and acts as a respiratory inhibitor to some plants. Juglone is poorly soluble in water and does not move far in the soil and will stay most concentrated in the soil directly beneath the tree.
Symptoms of juglone poisoning include foliar yellowing and wilting. A number of plants are particularly sensitive. Apples, tomatoes, pines, and birch are poisoned by juglone, and as a precaution, should not be planted in proximity to a black walnut.
— quote from Wikipedia
(credits are in the captions)