Grey fluffy fuzzy downy feather patches on the back and sides of House Sparrow (2 Viewers)

[01101001]

(Sorry for the title and clickbait; I wanted to put all the keywords in it.)

I've noticed that a significant proportion of House Sparrows of both sexes in the city centre of Warsaw (perhaps not representative of the whole city centre, though) have grey downy feathers on the back and sides that are long enough to obscure wing feathers in different places (the location and extent vary between individuals). I've had a look at images in the Macaulay Library, and I found photos of House Sparrows showing this trait from spring and summer (so it occurs not only in winter, i.e. now), which should rule out two possible explanations: keeping warm in winter and juvenile plumage. However, the fraction of House Sparrows with this trait seemed to be much greater (again, anecdotal observation) in the city centre than in the Macaulay Library, which comprises data from all habitats (sorting photos by quality may have skewed the results as well). I have also seen such patches in photos of Eurasian Tree Sparrows from the Macaulay Library, although they seemed to occur even more rarely than in images of House Sparrows from the same source. So, no hard and fast evidence, really--just some musings of mine. Anyway, I was wondering if this feature may somehow be correlated with the age of sparrows, with older birds having more grey fluffy bits on the back and sides. My tentative rationale: House Sparrows in cities have a lower mortality rate than average House Sparrows (less predators); Eurasian Tree Sparrows don't inhabit city centers in large numbers, so they are on average even more vulnerable to predation than the said average House Sparrows. I have no concrete evidence to back up my hypothesis, but I'd be interested to know if someone with a ringing/banding background has anything to say about it.

A similar query posted elsewhere: House Sparrow with grey, fluffy side patch. - FeederWatch.

EDIT: Upon reflection, maybe this title is just a tad too stupid. Anyway.

 

[01101001]

Photos to help get the message across/show the trait to those who haven't had the chance to observe it (although it appears to be common, so not sure if the latter applies).

 

[Alexander Stöhr]

Hello,
I cant see any clickbaiting here. Interesting thread. Tfs!

 

[01101001]

Present in at least some New World sparrows, too--so perhaps not unique to one genus or another (in particular, I mean the grey feathers between the wing and the mantle; the last picture is for comparison):

ML29663621 - White-crowned Sparrow (nuttalli) - Macaulay Library

Macaulay Library ML29663621; © Michael Rieser; Monterey, California, United States

macaulaylibrary.org

ML466875611 - White-crowned Sparrow (nuttalli) - Macaulay Library

Macaulay Library ML466875611; © Long-eared Owl; San Francisco, California, United States

macaulaylibrary.org

ML33038521 - White-crowned Sparrow (nuttalli) - Macaulay Library

Macaulay Library ML33038521; © Craig Fosdick; Santa Cruz, California, United States

macaulaylibrary.org

ML95731511 - White-crowned Sparrow (nuttalli) - Macaulay Library

Macaulay Library ML95731511; © Mark Schulist; Marin, California, United States

macaulaylibrary.org

* * *​

ML264126721 - White-crowned Sparrow (nuttalli) - Macaulay Library

Macaulay Library ML264126721; © Connor Cochrane; Marin, California, United States

macaulaylibrary.org

* * *​

Maybe these feathers have lost their compact structure over time due to excessive wear and not being replaced?

EDIT: [species] ([average lifespan], [oldest recorded])
House Sparrow (3 years, almost 20 years)
Eurasian Tree Sparrow (2 years, over 12 years)
White-crowned Sparrow (16 months, over 13 years)

EDIT 2: All individuals from above were photographed in the California Bay Area (Monterey just below it, in northern Monterey County), where White-crowned Sparrow is resident, and hence averts the perils of migration--similarly, House Sparrows and Eurasian Tree Sparrows are resident in (almost) all of their range.

 

[01101001]

Saturday Fun: I've recently (but already after I started this thread) overheard a poem about House Sparrows by the (reportedly quite bird-savvy) Polish poet Leopold Staff, in which they were described as grey. It turns out, a couple of scholars (both having 'sparrow' as their surname, lol) even wrote a paper about the significance of House Sparrows in his poetry, and their greyness is invoked in two other poems as well (which is interesting because I'd say House Sparrows are brownish rather than greyish overall, although they do have pale underparts, of course). While these mentions may have partly served symbolic purposes (grey being the most 'colourless' and pedestrian colour), I wonder if the writer's choice of words might have been influenced by the fact that a plurality of House Sparrows showed grey on their back at that time (and hence they perhaps appeared decidedly more grey than brown; for photos see above).

Now, I'm bending over backwards on this one, but back in the first half of the 20th century horse-drawn vehicles were still a very common--if not dominant--means of transport in Poland, and the presence of horses--from what I've read--is beneficial to House Sparrows because the birds have access to a reliable source of oats; I think the abundance of horse manure must have drawn insects as well, and House Sparrows need them for feeding their chicks. From what I've inferred from Wikipedia, Staff mostly led a city life. Before World War II (and perhaps also immediately afterwards) horses used to be quite common in Polish cities (so probably Eastern European cities as well), which together with many suitable nesting sites must have created very favourable conditions for House Sparrow (raptors have only begun to colonise city habitats in recent decades). Consequently, House Sparrows in cities were more numerous than nowadays and probably lived longer back then. Whether that has anything to do with the dominant colour (grey vs brown) associated with them remains to be determined.

 

[maplekong]

This is rather interesting... any developments? I don't see house sparrow often, but I found this, it may well be that they don't produce as much pigment as they get older. Can birds go grey in old age? | Discover Wildlife

 

[maplekong]

Apparently the size of their bib also varies with age and social status.

 

[01101001]

Very interesting, thanks a lot. No new developments yet, but I'll try to keep you posted.

 

[Ajord]

I came to this site because I saw the question about gray feathers on house sparrows. We had a house sparrow that we found abandoned when it was only a day or two old. She became a wonderful and greatly loved pet, and she just passed away at over 12 years old. We knew over the past month by her behavior that her time left with us would be short. The feathers on her back had gone almost completely gray. I assumed it was attributable to her advanced age, although I had no sources to confirm if that was the case, so I thought I would see what others on this site believe.

 

[delia todd]

Hi Ajord and a warm welcome to you from all the Staff and Moderators. I had no idea that House Sparrows lived so long.

I'm sure you will enjoy it here and I look forward to hearing your news.

 

[01101001]

Photos to help get the message across/show the trait to those who haven't had the chance to observe it (although it appears to be common, so not sure if the latter applies).

Limited loose grey feathering showing from under the mantle (similar to that in the pictures attached to post #2, except a bit less extensive), can also be shown by juveniles (aged by the presence of a bright yellow gape flange). Couldn't get a decent photo by phonescoping (sorry). Once again, a big thank you to @Ajord because now I think there still may be room for some research on the topic.

 

[Tammy D]

(Sorry for the title and clickbait; I wanted to put all the keywords in it.)

I've noticed that a significant proportion of House Sparrows of both sexes in the city centre of Warsaw (perhaps not representative of the whole city centre, though) have grey downy feathers on the back and sides that are long enough to obscure wing feathers in different places (the location and extent vary between individuals). I've had a look at images in the Macaulay Library, and I found photos of House Sparrows showing this trait from spring and summer (so it occurs not only in winter, i.e. now), which should rule out two possible explanations: keeping warm in winter and juvenile plumage. However, the fraction of House Sparrows with this trait seemed to be much greater (again, anecdotal observation) in the city centre than in the Macaulay Library, which comprises data from all habitats (sorting photos by quality may have skewed the results as well). I have also seen such patches in photos of Eurasian Tree Sparrows from the Macaulay Library, although they seemed to occur even more rarely than in images of House Sparrows from the same source. So, no hard and fast evidence, really--just some musings of mine. Anyway, I was wondering if this feature may somehow be correlated with the age of sparrows, with older birds having more grey fluffy bits on the back and sides. My tentative rationale: House Sparrows in cities have a lower mortality rate than average House Sparrows (less predators); Eurasian Tree Sparrows don't inhabit city centers in large numbers, so they are on average even more vulnerable to predation than the said average House Sparrows. I have no concrete evidence to back up my hypothesis, but I'd be interested to know if someone with a ringing/banding background has anything to say about it.

A similar query posted elsewhere: House Sparrow with grey, fluffy side patch. - FeederWatch.

EDIT: Upon reflection, maybe this title is just a tad too stupid. Anyway.

I was wondering the same thing about a sparrow I just saw that had fluffy, fuzzy downy sticking out from its right side, and was wondering if it was a juvenille? I am not an expert, and this is 9 months after your questions. I hope you get the answer because I would like to know as well. We just had at least 20 sparrows show up just before 1:00 p.m. CST.

 

[Tammy D]

I was wondering the same thing about a sparrow I just saw that had fluffy, fuzzy downy sticking out from its right side, and was wondering if it was a juvenille? I am not an expert, and this is 9 months after your questions. I hope you get the answer because I would like to know as well. We just had at least 20 sparrows show up just before 1:00 p.m. CST.

 

[KC Foggin]

Hi Tammy! I'm just going to jump in here to wish you a warm welcome from those of us on BirdForum! I hope you enjoy your time with us

 

[Tammy D]

Thank you, KC!! Do you get Mourning Doves? I cried when one of ours got chased by a red-tailed hawk and the Mourning Dove turned into our patio because it knows there is safety here. Unfortunately, it was flying scared and flew right thru the 21 feet of our covered patio, and hit the window right next to where I was sitting in my GCI folding rocker chair. It broke my heart. I said Oh, baby! And it looked up at me, bled from the beak and died. It knew I was the one feeding it, and our patio is about 21-foot by 31-foot, with food, water and shade. I put the poor thing in a cushioned box and checked on it every few minutes, but he/she never opened its eyes or breathed again. Luckily we haven't seen the hawk back. My husband jumped up from where he was cutting ledger stone and I was speaking to the dove, so the hawk high-tailed it out of there. But after 2 hours of checking every 10 minutes and no movement, I took our baby a mile away to a field, because I didn't want hawks thinking this was a songnird buffet yard . . . and put it out . . . But other than that, my first year of birding on eBird has been quite exciting, and I am loving it!

We put Sunflower Seeds out every couple days and fresh water daily, plus hummingbird nectar every couple days. And I have planted Zinnias, Potted Marigold, Borage near the Kale, Sunflowers, Petunias, Bachelor Buttons, Linaria Ferry Bouquet, Tall Phlox, Mums, Roses, Butterfly Bushes with Parsley beneath, and Hydrangea. So we have lots of butterflies including Monarchs, and so many birds: Mourning Doves, House Finches, Ruby-throated Hummingbirds, Black-chinned Hummingbirds, House Sparrows, American Goldfinch, Cardinals, Mallard Ducks, Killdeer (Spring but not Summer: Cowbirds, Red-winged Blackbirds, American Crows, Grackle, Black-eyed Junco).

It's so spectacular seeing birds this close-up! They love the fact that I started putting seeds on two plates in addition to the hanging Finch Feeder and Sunflower Seed Feeder just a few months into feeding them in the Spring 2023.

 

[S_Man]

My idea is that this is just the new plumage after the moult, which happens in July-August in Europe, then it gets worn out. Those feathers look very downy and fragile, so they might be worn or lost quite quickly...

Apparently Sparrows can moult at unusual times if they are stressed out, that could explain these pictures in Warsaw in the middle of the winter? I found this theory about "shock moults" on a French-Canadian website, that also mentions a possible record lifespan of 23 years in captivity!

 

[Tammy D]

My idea is that this is just the new plumage after the moult, which happens in July-August in Europe, then it gets worn out. Those feathers look very downy and fragile, so they might be worn or lost quite quickly...

Apparently Sparrows can moult at unusual times if they are stressed out, that could explain these pictures in Warsaw in the middle of the winter? I found this theory about "shock moults" on a French-Canadian website, that also mentions a possible record lifespan of 23 years in captivity!

Thank you, S_man!

 

[01101001]

That's certainly a very interesting theory, and it could even potentially explain why the phenomenon appears (?) to be more widespread in city dwellers.