Monthly Archives: February 2014

I Can Sound Pretty

Songbirds, Vocalizations

Blue jay in winter (photo by Cris Hamilton)

As the days get longer the birds have started to sing again.  Jessica Manack reminded me that one of those songs is quite a surprise.

The blue jay’s typical call is unmistakeable and brash. We usually see him do it because he draws attention to himself when he says “Jay.”

He can also make a wide variety of other sounds, some of which are really odd: Try this link at the Macaulay Library.

But during the courtship season he says KWEE-de-lee, a sound so melodic you think it couldn’t be made by a jay.

When you hear this call, look for the bird and you’ll find him doing rapid deep knee bends, raising and lowering his entire body as he calls.

“I can sound pretty,” says the blue jay.  “I just don’t want you to notice.”

(photo by Cris Hamilton)

Under Construction

Birds of Prey, Nesting & Courtship

As you saw last weekend there are still crowds of bald eagles gathered along North America’s rivers waiting for winter to end.  They can’t go home and begin courting until the ice breaks up.

Meanwhile Pittsburgh’s eagles have a head start on the nesting season because our rivers don’t freeze over.  The pair at Hays has already progressed to the finer points of nest construction.  They finished the foundation (large sticks) and the bowl (small sticks) and are now working on the nest lining (soft grasses).  Sometimes they bring a fish and have a snack at the nest.  When the lining is complete, egg-laying won’t be far away.

When you watch the Pittsburgh Hays eaglecam you’ll notice how different eagles’ habits are from peregrines’ behavior.  Peregrines don’t “build” a nest, they never use sticks or soft grasses, and they almost never eat at the nest unless they have young in it. This difference is driven by their food and habitat needs:  bald eagles eat fish and nest in trees near water, peregrines hunt birds on the wing and nest on cliff ledges.

Bald eagles also nest earlier than peregrines so watch the Pittsburgh Hays eaglecam for live updates.  If you miss the action, browse the archives here.

 

(bald eaglecam video by PixController, streaming provided by WildEarth)

Clean Your Bird Feeders

Musings & News

House finches in Phoenix, Arizona (photo by Kevin McGraw, Arizona State University)

In the depths of a bitter winter it’s a challenge to wade through ice and snow to refill the feeders and even more challenging to pull in those feeders and clean them.  Every day I put it off.  This message is for all of us who’ve been procrastinating.

A new study published this week in PLOS One has found a direct link between urbanization and avian infections.  The denser the human population, the sicker the birds.

Mathieu Giraudeau, Melanie Mousel, Stevan Earl, and Kevin McGraw studied canarypox and Coccidian infections in male house finches (Haemorhous mexicanus) in the Phoenix, Arizona metro area.  Like chicken pox, canarypox forms blisters on the skin.  Coccidiosis is caused by parasites in the intestinal tract, spread by infected feces or ingestion of infected tissue.  During the study, house finches with coccidiosis were found to be fatter but unable to absorb the nutrients they ate.

At each site where they trapped and diagnosed house finches, the researchers also noted the land use patterns and habitat.  Then they looked for correlations and found:  The denser the human population and the less natural the habitat, the higher the number and intensity of infections in the birds.

Why?

According to Science Daily: “Much like the spread of human disease in populated areas, urban centers can foster increases in multiple disease types in wild animals,” said Kevin McGraw, senior author of the study. “We are now investigating the mechanism underlying this observation.”

And from the PLOS One article: “Humans may facilitate infections in these birds via bird feeders (i.e. horizontal disease transmission due to unsanitary surfaces and/or elevations in host population densities) and/or via elevations in other forms of physiological stress (e.g. corticosterone, nutritional).”

Interestingly this photo from the study may hold a visual clue to the health of these two birds.  Male house finches should have red faces like the bird on the left.  Those with yellow have not absorbed enough carotene to produce red feathers.  Perhaps the yellow-faced bird has coccidiosis.

Bottom line:  Clean your bird feeders.

Read more here in Science Daily or the research article in PLOS One.

 

p.s. Click here for information on how to clean your bird feeders.

(photo by Kevin McGraw, Arizona State University)

Prefers To Raise An Only Child

Beyond Bounds, Bird Behavior
Scarlet macaw (photo from Wikimedia Commons)
Closeup of scarlet macaw, Gran Canaria (photo from Wikimedia Commons)

5 February 2014

Last fall Parrot Confidential introduced us to the ARA scarlet macaw recovery project in Costa Rica and a bird named Geoffrey who was abandoned by his mother.  I assumed at the time that Geoffrey was rescued because his mother was new to motherhood and unskilled in raising her first brood.

But no.  Scarlet macaws have a very unusual parenting strategy.  The female lays up to four eggs but when the eggs hatch the parents choose just one of the nestlings — usually the first — and shower it with attention.  The rest are ignored, unfed, not brooded.  They die within three weeks.  The parents purposely raise an only child.

I learned about this very unusual behavior in an article in wired.com about the Tambopata Macaw Project in southeastern Peru.  Since 1989 the project has collected a wealth of information on scarlet macaw biology and behavior including the birds’ habit of raising only one chick each year.  From Nadia Drake’s article:

Observations suggest that this outcome is one of choice, rather than resource limitation. So far, the reasons why are still a mystery. This parenting strategy seems to be unusual even among birds, which often lay extra eggs and then distribute limited resources among chicks with brutal efficiency.
…
The truth is that macaw chick mortality does not appear to be the accidental or inevitable result of scarce resources.

“This is death by neglect,” said ornithologist Donald Brightsmith of Texas A&M University. “Complete and utter neglect.”

— Wired Magazine: Tambopata Macaw Project

Raising only one chick per brood is an unfortunate trait for a bird with a declining population but it explains why the ARA Project has a natural supply of baby scarlet macaws — every nest has an abandoned nestling.  By raising the “extra” birds the project boosts the local population.

Scarlet macaws have a reason for choosing to raise an only child.  We just don’t know what it is yet.

Read more here at wired.com.

(photo from Wikimedia Commons. Click on the caption to see the original)

Schenley’s Oak Wilt Trees Are Coming Down

Schenley Park, Trees

Oak stump upended to prevent the spread of oak wilt (Joseph O'Brien, USDA Forest Service, Bugwood.org)

Don’t be surprised when you see trees being felled this month at Prospect Drive in Schenley Park.  An acre of diseased trees must be clear-cut to protect the park’s healthy oaks.

Councilman Corey O’Connor held an informational meeting last night where we learned about the project from City Forester Lisa Ceoffe and Pittsburgh Parks Conservancy’s Erin Copeland.  They described oak wilt, its treatment, and the affected area in Schenley Park which I’ve drawn on the tiny map below.  Click on the map for a better view in Google.

Location of the Oak Wilt zone in Schenley Park, February 2014 (screenshot of shared Google map)

Here are some of the 55-60 trees that will come down, marked with blue logging paint last summer. Many of them are 100 years old.
Oak wilt trees marked for removal from Schenley Pak (photo by Kate St. John)

Why is the area so large and why must it be clear cut?

Oak wilt is caused by a fungus that doesn’t spread easily but can kill a tree in 30 days.  The fungus travels in the oak’s vascular system and when the tree detects it it blocks those vessels — the arboreal equivalent of a stroke.  Watch the 13 minute video here to see how this happens.  You know the oaks are sick when you see browning leaves in mid-summer.  This is the only sign.

Oak leaves showing oak wilt (Joseph O'Brien, USDA Forest Service, Bugwood.org)

The infection travels through an entire stand because the oaks are joined underground.  When their roots touch, they graft to share nutrients and, sadly, disease.  We only see the symptoms in summer so a large area can become infected before anyone notices.

Oak root graft (photo by Ronald F. Billings, Texas Forest Service, Bugwood.org)

 

Once the fungus has taken hold, an infected tree is doomed.  The only way to save nearby healthy trees is to trench the perimeter of the infection(*) and remove all the trees inside the circle.  Sap beetles can carry the infection so the logging must be done in winter when the sap isn’t running.  (Note!  Don’t prune your oaks in spring and summer.  This opens them to oak wilt.)

When the logging begins in about 10 days, Prospect Drive will be closed each morning when the equipment arrives and reopened when Davey Tree is done for the day.  Signs will be posted explaining what’s going on and Davey Tree will have brochures for those who want to know more.  The site is easily visible from the Boulevard so the City expects a lot of questions.  Now that you know what’s going on, spread the word.

By the end of February the area will be empty, but not for long.  Site restoration begins March 22 with a tree planting conducted by the Pittsburgh Parks Conservancy.  Who’s going to plant the trees?  Volunteers!

Schenley Park needs you on Sunday March 22, 10:00am to 2:00pm, rain or shine.  Click here or call 412-682-7275 to learn more about signing up.

 

(photos from Bugwood.org by Joseph O’Brien, USDA Forest Service, Bugwood.org and Ronald F. Billings, Texas Forest Service. Screenshot of shared Google map. Click on the map to see details on Google.)

(* Trenching prevents healthy roots from growing into the infected zone.)

UPDATE 2 June 2014: Click here for the most recent update.

Please Make Yourself At Home

Peregrines

Peregrine at the Gulf Tower, 31 Jan 2014 (photo by Ann Hohn)

Breaking news!  The Downtown peregrines are considering a move back to the Gulf Tower.

On Friday morning Ann Hohn looked through the blinds at Make-A-Wish and … Oh my!  There’s a peregrine out there!

It’s been two years since the Downtown peregrines have frequented the Gulf Tower.  They left in the winter of 2011-2012, scared off by the rooftop lighting project.  The rooftop lights were fully installed long before the 2013 nesting season so we thought they might come back to Gulf last year, but they didn’t even try.  Instead they nested again at their hidden location on Third Avenue where they fledged four young, all of whom landed on the street (not good!).  Unlike the 40-story Gulf Tower their Third Avenue nest is only 12 stories high.

Though the Gulf Tower falconcam isn’t streaming video, it’s still turned on with motion detection so I pulled the snapshots to see how often the peregrines have visited.

On Thursday, January 30 they bowed at the nest.
The Downtown peregrines court at the Gulf Tower nest, 31 Jan 2014 (photo from the National Aviary falconcam at the Gulf Tower)

 

On Friday, Ann saw them in the morning and afternoon and heard a lot of courtship noise (e-chupping).  You can see that the female ate a big meal.  Notice her very full crop.
Peregrine visiting the Gulf Tower nest, 31 Jan 2014 (photo by Ann Hohn)
Ann tried to read this bird’s bands to confirm her identity but the bird kept her leg feathers low.

 

On Saturday the birds again stopped by in the morning and afternoon.  If these peregrines are the same individuals who nested here before, the first photo is Dori, the second one is Louie.  (No visit yesterday, the weather was too miserable.)
Peregrine at the Gulf Tower nest, 1 Feb 2014 (photo from the National Aviary falconcam at GulfTower)

Peregrine at the Gulf Tower nes, 1 Feb 2014, 2:25pm (photo from the National Aviary falconcam at Gulf Tower)

 

Their repeated visits are a very hopeful sign but they’re still tentative at this point.  The peregrines are wary because they’ve been scared off before.  If humans appear outdoors on the Gulf Tower roof or at the nest, it could scare the birds back to Third Avenue.  Yes, we know the camera cover is dirty but we’re afraid that cleaning it will spook them.

Ann has alerted Gulf Tower maintenance and we’ll have a dialog about ways to retain the peregrines.  We really want them to nest there this year.

Dear Downtown peregrines:  Please make yourself at home.

 

(photos by Ann Hohn at Make-A-Wish and the National Aviary falconcam at Gulf Tower)

p.s. There is no link to the Gulf Tower camera yet.  I’ll let you know when it’s ready.