Is It Spring Yet? Asks the Starling

Phenology, Songbirds
European starling in winter plumage (photo from Wikimedia Commons)

12 January 2023

I know it’s only 12 January but a starling told me on Tuesday that spring is coming soon. I could see it in his beak.

Most of the birds that spend the winter in Pittsburgh wear the same colors all year long. Blue jays, chickadees and red-tailed hawks don’t change their look from winter to spring. European starlings (Sturnus vulgaris) do make a change but it’s subtle.

In winter they live up to their name with “starry” spotted feathers, dull dark pink legs, and gray-black beaks. When spring comes their spots wear off, their legs become brighter red and their beaks turn yellow.

Last Tuesday I saw a starling whose beak was turning yellow, though still black-tipped like the one pictured below.

Halfway to spring plumage (photo from Wikimedia Commons)

His ultimate goal is this glossy crisp appearance.

European starlings in breeding plumage (photo from Wikimedia Commons)

Starling beaks usually start changing in February. Is spring coming sooner than usual or is that starling ahead of the game?

(photos from Wikimedia Commons; click on the captions to see the originals)

Why Does Roman Concrete Last Forever?

Musings & News
Concrete in the Roman ruins of Tróia, Portugal (photo from Wikimedia Commons)

11 January 2023

Cement cracks. Rocks erode. Why does ancient Roman concrete last for thousands of years while ours falls apart in only 50?

The 2,000 year old concrete at the Roman ruins of Tróia, above, is in good shape while a 1960’s concrete wall below is so degraded that its rebar supports were already rusting by 2012.

Degradation of concrete from the 1960s (photo from Wikimedia Commons, Germany, 2012)

The difference is how we mix our cement that binds the concrete together. This is a story of recipes and chemistry. (Concrete = cement + sand, gravel, rocks.)

  • Modern day Portland cement is made by baking limestone and clay minerals at 600oF, then grinding the result and adding gypsum.
  • The Romans made cement from slaked lime (quicklime+water), volcanic ash and water.

Scientists discovered in 2017 that volcanic ash + seawater were the secret ingredients that made Roman concrete strong. Those two components were conveniently available in ancient Italy but not economically feasible today. Recently a team of scientists, headed by Admir Masic of MIT, discovered an inexpensive Roman ingredient that helps concrete heal itself.

Cement, when exposed to water, can heal very small cracks in concrete by minutely dissolving and recrystallizing. However the cracks must be very tiny in Portland cement-based concrete in order for this to happen — smaller than 0.2 to 0.3 millimeters across (0.0078 to 0.0118 inches).

During the study, the team made Roman-inspired concrete using slaked lime and found that it can heal cracks up to 0.6 millimeters across (0.0236 inches), twice the tolerance of Portland cement.

If our cement used this Roman innovation it would save a lot of damage control.

Find out more in Science Magazine at: Scientists may have found magic ingredient behind ancient Rome’s self-healing concrete

p.s. Slaked lime = quicklime + water. Quicklime is made by baking lime or seashells in a kiln to split the calcium carbonate (CaCO3) into plain calcium oxide (CaO) + CO2. Quicklime is unstable and will spontaneously react with CO2 unless it is slaked with water to set as lime plaster or mortar. — parapharased from Wikipedia

Calcium oxide powder a.k.a. quicklime (photo from Wikimedia Commons)

Nestbox Maintenance With Peregrines

Peregrines

10 January 2023

Yesterday morning with help from Pitt Facilities Manager Dante Bongiorni, Gary Tuscan of the National Aviary and I conducted annual maintenance at the Pitt peregrine nestbox and falconcams.

As we came up the elevator we had no idea that Ecco was preening at the nest with a bit of fluff on his head. He must have alerted Morela because she was already watching us through the window when we arrived indoors. I should have taken her picture but was too preoccupied with the task ahead:

  • Clean the camera covers to remove the dirt that distorts the images.
  • Remove large debris from the gravel surface.
  • Assess deterioration at bottom left of the back wall. If it’s a hole, measure the wall and return later to install a replacement panel.
Deterioration on the back wall of Pitt peregrine nestbox (photo, October 2022)

I was surprised when Morela strafed the nest rail and kakked when we reached the nest. This is new behavior for January, the non-breeding season, but it may be that our presence in the room near the nestbox was unusual since that room has not been used for a long time. Morela must have been remembering Banding Day last May.

I cleaned the cameras and Gary measured the back wall (slideshow above). The wall has a hole so Gary must return to fix it. I’ll have to come back, too, because the camera is still rather dirty. Before and After shown below.

Before and After: The sun lights up the dirt on the snapshot camera (photos from the National Aviary snapshot camera at Univ of Pittsburgh)

When we come back Morela will get another chance to feel triumphant that we left because she chased us off. 😉

(photos from the National Aviary snapshot camera at Univ of Pittsburgh)

Fewer Hybrid Golden-Wings Thanks to Climate Change

Bird Behavior, Climate Change
Golden-winged warbler (photo from Wikimedia Commons)

9 January 2023

Golden-winged warblers (Vermivora chrysoptera) and blue-winged warblers (Vermivora cyanoptera) do not look or sound alike but they are well known to hybridize. Because of this ornithologists used to worried that the more numerous blue-winged warbler would force the golden-winged out of existence. Then a 2016 genetic study showed no need to worry — they are very closely related. Now a 2022 study shows that hybridization will become less likely thanks to climate change.

Blue-winged warbler (photo from Wikimedia Commons)

In 2016 we learned that golden-winged and blue-winged warblers are virtually the same bird — 99.97% genetically alike! No wonder they interbreed.

Put another way, the striking visual differences between Golden- and Blue-winged warblers could be considered akin to the differences between humans with and without freckles. Golden-wings and blue-wings have even less genetic differentiation than two subspecies of the Swainson’s Thrush.

— All About Birds: Mixed Wing Warblers: Golden-wings and Blue-wings are 99.97 percent alike genetically

Their colors and songs fooled us so we called them hybrids and even named them Brewster’s and Lawrence’s warblers, but the difference is moot to the birds themselves. This illustration embedded from All About Birds, shows their four color phases governed by a dominant/recessive throat-color gene.

Warblers and Hybrids: Blue-winged, Brewster’s, Golden-winged, Lawrence’s (embedded from Cornell Lab’s All About Birds; Illustrations by Liz Clayton Fuller, Bartels Science Illustration Intern)

If you’re still worried about hybrids, the newest study should put your mind at ease. Entitled “Change in climatically suitable breeding distributions reduces hybridization potential between Vermivora warblers,” it maps the birds’ past and present breeding ranges and models their future under 6 climate scenarios.

Historically (1932-1997) the warblers’ ranges overlapped a lot but by 2012-2021 it was evident they were moving apart. Climate change has moved the golden-wing’s preferred cooler habitat to the north and higher elevations.

The future will move their ranges even more, shown in six scenarios below. The left column shows climate altering emissions peaking in 2040 and then declining. The right column shows emissions continuing to rise through 2100.

Predicted climate suitability for Golden-winged Warblers (yellow) and Blue-winged Warblers (blue) distributions under future climate scenarios (https://onlinelibrary.wiley.com/doi/full/10.1111/ddi.13659).

Unfortunately climate change may force one or both warblers out of existence. Map (d) is the only happy one for both of them but they will disappear as breeding birds in western Pennsylvania.

Don’t worry about golden-winged warbler hybrids. The real problem is climate change.

* Read more about golden-wing and blue-wing relatedness in All About Birds, Living Bird Magazine: Golden-Winged And Blue-Winged Warblers Are 99.97 Percent Alike Genetically.

* See the breeding range study at Wiley Online: Change in climatically suitable breeding distributions reduces hybridization potential between Vermivora warblers.

(photos from Wikimedia Commons, illustration embedded from All About Birds, maps are open access at Wiley Online Library)

White-throated Sparrows Have Four Sexes

Bird Anatomy, Bird Behavior, Songbirds
White-throated sparrow colors and sexes — green arrows show the only combinations that can mate successfully (photos from Wikimedia Commons)

8 January 2023

White-throated sparrows (Zonotrichia albicollis) come in two color morphs with either white-striped or tan-striped heads. The color tells us nothing about the sex of the bird because both morphs contain males and females. Last week a new article about a 2016 study reiterated the white-throated sparrow’s affinity for mating with the opposite color morph. It’s deeper than just a preference. These birds cannot reproduce with their own color.

Thirty years of research by Elaina Tuttle and Rusty Gonser into the genetics and behavior of white-throated sparrows revealed a mutation in chromosome 2 that makes it impossible for same-color-morph birds to reproduce. The birds seem to know this and only look for mates among birds of the opposite color. Instead of half the population as possible mates, fellow researcher Christopher Balakrishnan points out that “One individual can only mate with one-quarter of the population. This bird acts like it has four sexes.”

  • White-stripe Male
  • Tan-stripe Male
  • White-stripe Female
  • Tan-stripe Female

A system of four sexes is quite rare and there’s a reason. As Balakrishnan says, “it is evolutionarily unstable and one of these alleles will ultimately go extinct.”

White-throated sparrows have declined 69% in the U.S. over the past 50 years and overall (including Canada) by 33%. Are they declining because of habitat loss? window kills? Is their four-sex system also taking a toll? If so they’re probably the only species with that challenge.

Read more in these two articles where I obtained the quotes above: IFLScience: Meet The Sparrow With Four Sexes and NATURE: The sparrow with four sexes.

(four photos above are from Wikimedia Commons at these links: top left, top right, bottom left, bottom right)

A Few Things Seen

Peregrines, Schenley Park, Trees
A red oak felled at Anderson Playground in Schenley Park, 30 Dec 2022 (photo by Kate St. John)

7 January 2023

This week’s rain dampened outdoor activities but there were still some things to see.

Chainsaw tree “trimming” continues in the city. This red oak had a hollow core so it was chopped down in late December at Anderson Playground in Schenley Park. Can you count the rings and determine its age?

On 3 January rain flecked the camera as Ecco stopped by for a visit. Notice how wet his head is!

On 4 January the rain finally stopped and the moon shone at 8pm.

When the cold snap ended on 28 December the ice thawed and the creeks began running again. Listen to the sound of Panther Hollow Run in Schenley Park on 30 December 2022.

(nest photos from the National Aviary snapshot camera at Univ of Pittsburgh, all other photos and video by Kate St. John)

Favorites of 2022

Beyond Bounds
Baltimore oriole, 2022 (photo by Steve Gosser)

6 January 2023

Photographers often look back at the end of the year and choose their favorite photos. On this first Friday in January sit back and enjoy 2022 favorites from Steve Gosser and Brad Balliet @BalliettBrad.

Steve Gosser lives in Pittsburgh so I sometimes see the exact same birds he does but they never look as good as his photos, two of which are pictured here.

Marsh wren doing a split, 2022 (photo by Steve Gosser)

Steve packed 38 photos into his 2022 favorites on Facebook.

Brad Balliett of New York put together a 2+ minute video on Twitter.

I’m looking forward to favorites in 2023.

(photos by Steve Gosser, tweet by Brad Balliett; click on the captions to see the originals)

Dead to Alive — Just Add Water

Plants & Fungi
Dried Selaginella Lepidophylla appears to be dead (photo from Wikimedia Commons)

5 January 2023

How long does it take for the dead-looking plant above to look like the one below?

The dead ball is the exact same plant as the one below: Selaginella lepidophylla, native to the Chihuahuan Desert.

Selaginella Lepidophylla after humidification (photo from Wikimedia Commons)

See an animation of what happens when you add water in this vintage article.

The Resurrection Plant

p.s. The one pictured above opened quickly at first. It took 24 hours to turn green.

(photos from Wikimedia Commons; click on the captions to see the originals)

Was The Snow Really Deeper When I Was A Kid?

Climate Change, Weather & Sky
Snow on sweet gum seed balls, Pittsburgh, 17 December 2020 (photo by Kate St. John)

4 January 2023

Rain. Rain. Rain! For two days it’s been raining in Pittsburgh while the high temperature holds at 61oF. Total rainfall will be 1.4 inches, some of which splashed the Cathedral of Learning falconcam.

Rain distorts the Cathedral of Learning falconcam, 3 January 2023

If the weather had been below freezing we’d be looking at 14 inches of snow! I’m glad it isn’t snowing but heavy rain in January got me thinking … Wasn’t the snow deeper when I was a kid?

I grew up in Pittsburgh so my memories of winter apply to where I live today, but are my memories distorted? Using Pittsburgh’s historical snowfall data I compared my 12 years of growing up in Pittsburgh(*) to the most recent 12 years.

The answer is mixed. There was more snow in winter when I was a kid (maximum winter total and highest minimum), but both the highest and lowest snowfall per month both occurred in the recent past — in fact in the same winter of 2020-21.

The wild swings in snowfall nowadays mirror the wild swings in temperature.

Remember how bitter cold it was only 11 days ago? Look at the temperature swing then (Christmas Eve 2022) and now (3 January 2023)!

So the answer is Yes & No. Yes, there was more snow in Pittsburgh when I was a kid. But, No, the snow is deeper today on rare occasions.

Curious about snowfall in Pittsburgh? Check out the historical data at NWS Pittsburgh and the Rain to Snow Calculator here.

(*) The span is 12 years because I moved to Pittsburgh when I was 6 years old.

(photo by Kate St. John, maps and data from the National Weather Service)

Winter Birds at the Beach

Bird Behavior, Water and Shore
Sanderlings in December (photo from Wikimedia Commons)

3 January 2023

When we think of the beach in winter it sounds pretty bleak but not if you’re a birder. Shorebirds, sea ducks, loons and gulls leave the icy north to winter on the Atlantic and Pacific coasts where they hang out on beaches or just offshore, especially near jetties.

If you can’t travel far from Pennsylvania, visit the New Jersey shore to see thousands of wintering birds. GetToKnowNature describes what you’ll see in her video “Welcome to the beach in winter.” Click here or on the screenshot below to see it on Instagram (you don’t need an account to see it) or here for YouTube.

Screenshot from GetToKnowNature winter beach video on Instagram

(photo from Wikimedia Commons, screenshot from GetToKnowNature video on Instagram)