Good Morning from Mary Whitcomb and Clem! Mary wrote that he was back this morning at 7:15 for grape jelly in the feeder.  It was thirteen degrees below zero! Tough little bird, but thanks to Mary, he's getting the nourishment he needs to make it through, we hope! He's well puffed out with insulating feathers in this photo, his only way of keeping his body temperature regulated.

Mary had reached out to Bryan Pfeiffer about Clem and later, my question about whether Clem might have added feathers due to the cold. Bryan in turn contacted his friend, Hugh McGuinness in Washington, D. C.

Here is their discussion, via e-mails:

 

On 27/12/2017 20:34, Hugh McGuinness wrote:

After looking at the photos I am not convinced that the Baltimore Oriole has grown an abnormal number of feathers. I wonder whether any bird can increase its feather count at all during the course of the annual cycle, and I leave that question for Dr. Prum to answer.

 Hugh McGinnis
Washington, D.C.

Dr. Richard Prum wrote in response to Hugh's inquiry:Bryan, Mary, and Hugh,

Fascinating question! Is there adaptive phenotypic plasticity in plumage in response to extreme temperature challenges? the quick answer is, I think, no!

There are a few ways this could happen in birds. One- birds could develop new feather follicles and add to the total number of feathers.  or Two- birds could grow new kinds of feathers-like down- from the existing feather follicles, or three- birds could grow better quality feathers- denser, or with more downy portions- from existing feather follicles.

I am off line in Colombia, so I can't check on the details of Oriole molt schedules! But most 9-primaried oscines have a molt in the fall prior to migrating which would be the source of the basic or "winter", non-breeding plumage.

I think the possibility of all three alternatives is very small. Birds usually develop all the follilcles they will ever have in the embryo. A few are added a bit later, but these are filoplumes- little tiny feathers with mostly sensory function. So, the bird couldn't up the number of total follicles or feathers.

The molt that precedes the winter would also happen BEFORE any data about extreme temperatures was available. So even if it could do 2 or 3, it wouldn't have the necessary data when it grew this plumage during the fall before the onset of extreme weather.

Molt sequence itself is very hard wired, requiring all sorts of responses of hormones and day length, and it occurs under very rigid timing. The one important piece of plasticity is whether to forgo the molt of certain feathers entirely, but this mostly occurs in younger birds, and is basically an incomplete molt.

Birds do not have the path available to mammals- which have a cohort of follicles that stays empty for weeks or months between molts. So, mammals can have more hair in the winter than the summer by having a greater % of all follicles with hair. Those "lush" eye lash prescriptions work by reducing the lag between eye lash replacement after molt so that a greater % of all eye lash follicles are holding hairs. Birds don't have this option.

SO, I don't think this bird has more feathers. It could, and obviously is, fluffing its plumage with its feather erector muscles which creates a greater volume of trapped air near the skin, and acts exactly like a down jacket. This is key to survival for birds.

This oriole's body temperature is probably close to 104˚F (41 or 42 ˚C). So it can lose  a lot of heat! The most important thing is having enough calories during the day to make it through the night. Lots of wintering birds survive each night on the food eaten that day! So, ice storms, which covers all the food, are actually worse than extreme cold. That said, there is a real limit to what an oriole can do! I would doubt it can survive many days with temps below 10˚F, and night temps below 0˚F.

Good luck buddy!
All the best, RIck




I'm pretty sure Dr. Prum will be interested that Clem is still very much alive and surviving not only nights below zero, but days as well. This may be the toughest little bird ever. I'm betting if he does survive until spring, next fall he'll be leading the flock south!

Diane Rossi reported it was 24 degrees below zero at her house this morning. Our low was 13 below. However, at 9:45 a.m., it's overcast and still 4 below. So fare, there's no wind. That wind was really brutal yesterday. We don't have to go anywhere for the next several days, so, with plenty of food in the pantry and a willing lap-cat to help keep us warm, we're going to hibernate for the duration!

Mary just sent more photos and this message:

 Good morning Jane,  Clem is getting quite the reputation for being remarkable and amazing on this 20th day of survival.  Bryan Pfeiffer is posting him on his blog again either today or on Saturday.  I brought the feeder in last evening to wash it because the jelly was making quite a sticky mess on it and in the sunflower seeds.  : )  He actually wolfed down alot more jelly from this container.  He’s either more hungry or he prefers eating out of it.   Mary