Spring is moving north and so are the robins. This week a big wave arrived after Monday's snow. Now that they're here, how soon will they nest?
Robins nest later the further north you go. In 1974 Frances James and Hank Shugart were curious about the conditions that governed their nesting times throughout the U.S. Using climate data and Cornell nest watch information from 8,544 robins' nests they developed a model that predicted when robins would nest in a particular region.(*)
The model shows that robins cue on weather. Hatching is timed to occur when local humidity is 50% and temperatures are between 45 and 65 degrees Fahrenheit. By April 23, Pittsburgh's highs and lows are exactly in that range so our birds are getting ready. Here's what they're up to:
Robins spend 5-7 days building their first nest of the season.
Egg laying begins 3-4 days after first nest completion.
Eggs are laid one per day for a clutch of 3-4 eggs.
Incubation lasts 12-14 days.
From nest building to hatching, the first nest takes 26 days. (Subsequent nests take less time.)
Our robins should be nest building right now except for one thing: Do they have enough mud to begin construction? Has the mud been frozen?
Watch the robins in your neighborhood to see what stage they're in. Join Cornell Lab's Nest Watch program and your data can become the basis for studies like James' and Shugart's that broaden our knowledge of birds.
(Credits: photo by William Majoros on Wikimedia Commons. Click on the image to see the original.
Today’s Tenth Page is inspired by page 260 of Ornithology by Frank B. Gill, portions of which are quoted(*) in this article.)
If you knew you'd get better food than what you already have if you just waited, would you wait?
Alice Auersperg and her team at the University of Vienna’s Department of Cognitive Biology tested 13 Goffin cockatoos (Cacatua goffini) to see if they would refrain from eating a lesser quality food if they knew a better one was coming. Until this experiment, only primates and corvids had shown this level of self control.
In the video Muffin is shown two nuts and offered a less preferred pecan. He takes the pecan but can see a yummy cashew waiting out of reach on the researcher's left hand. If he waits and returns the pecan, he'll get the cashew.
So he waits. Even though he can smell and taste the pecan he holds in his beak, he merely rearranges it and paces to take up the time.
Eventually the researcher offers him her empty right hand. He returns the pecan and gets the cashew.
In the 1970's this level of self restraint shown by children in a test using marshmallows was ultimately correlated to greater success in life. Those who can delay gratification will go far.
Conventional wisdom says that birds can't smell anything, but this isn't so.
Did you know they use their sense of smell to guide them on migration and that it's more important for navigation than magnetic field detection?
Back in 2009 the Max Planck Institute of Ornithology ran an experiment to see which mattered more. During fall migration they captured 67 gray catbirds and put tiny radio transmitters on them. 48 were captured at the Princeton field station, 19 were captured in Illinois and delivered overnight to New Jersey. This presented the Illinois birds with a big navigational challenge.
All of the birds were fitted with tiny radio transmitters and divided into three groups. One third had scramblers to impair their magnetic field sense, one-third had a temporarily impaired sense of smell, one third had no impairments.
When released to continue their migration, where did the birds go?
The juvenile birds performed as expected. Having never made the trip before they had no mental map so they flew due south to Cape May and had to cross Delaware Bay at its widest point.
Unimpaired adults and those with an impaired magnetic sense used their mental maps and sense of smell to fly southwest and avoid Delaware Bay. Even the "blown off course" Illinois birds flew west or southwest to correct for their new location.
But those who couldn't smell anything were a little lost. The adults with mental maps fell back on their original inborn guidance system and flew due south. So, yes, their sense of smell matters a lot more than we expected.
Next month gray catbirds will arrive in Pittsburgh from their winter range in Florida, Cuba and the lands surrounding the Gulf of Mexico. When they get here, you can be sure they sniffed their way north.
I wonder what they're smelling...
(photo by Alan Vernon from Wikimedia Commons. Click on the image to see the original)
This beautiful small goose is heading toward extinction.
The red-breasted goose (Branta ruficollis) breeds in arctic Russia and winters at only five sites along the Black Sea in Bulgaria, Romania and Ukraine. Though protected by law it faces many challenges, from land use changes to illegal hunting.
It was already listed as threatened when suddenly, 10 years ago, half the population simply disappeared. 50,000 birds. Gone. No one knows what happened. Did they forsake the Black Sea for a new winter home? Did something go radically wrong where they breed?
Now listed as endangered on the IUCN Red List, the red-breasted goose population continues to decline. Another such disappearance would mean the end so researchers from Britain's Wildfowl & Wetlands Trust and the Bulgarian Society for the Protection of Birds have fitted 11 red-breasted geese with tags to track their movements.
Nine geese received GPS data packs that will log their winter locations at the Black Sea. Two received satellite tags that will track their migration from Bulgaria to the breeding grounds in Siberia.
Snow again! We are so ready for spring here in Pittsburgh.
The crocuses bloomed early last week but were slammed shut on Wednesday by a low of 200F. Daffodil leaves emerged and paused. Don't even ask about tulips.
But Spring is south of us and it's on its way. There's a rule of thumb that says Spring moves north 13 miles a day.
Here's an easy way to watch its progress.
Journey North has a Tulip Test Garden website where observers report when leaves emerge and flowers bloom from the tulip bulbs they planted last fall. Many of the tulip gardens are student projects at elementary schools such as Della Kurtzhals' class at Clarion Area Elementary School in Clarion, PA.
So how far away is spring? At Providence Day School in Charlotte, NC the first tulip bloomed on March 18. Using the rule of thumb, here's my guess at blooming times in Pittsburgh and Clarion:
Pittsburgh is 372 air miles north of Charlotte so I estimate our first tulip will bloom on April 15.
Clarion is about 430 miles north of Charlotte so their tulips will probably bloom on April 20.
This is just an estimate. Actual blooming times may vary. I won't be charged like Punxsutawney Phil was for "misrepresenting spring." (Click here to read about the charges made against him in Hamilton, Ohio. The comments are hilarious.)
So while your garden is covered in snow, rest assured that spring is moving north. You can see it approaching on the Tulip Test Garden map.
(photo from Wikimedia Commons. Click on the image to see the original)