Rose Gulls (1 Viewer)

Gulls with a cap (Black-headed Gulls, Little Gulls etc.) have (sometimes) a rose glow on their (white) plumage. Some birders say it comes by the food (shrimps a.s.o.), or by the glandfat, or by the hormones in the breeding-season.

Does anybody know the real reason (with arguments)?

Thnx,
Adri
www.vogeldagboek.nl

Hi Adri,

May I wish you a warm welcome to Birdforum on behalf of all the Admin, Staff and Moderators. I am sure you will find everyone here friendly and helpful.

I have noticed this myself occasionally although I don't know the cause. I look forward to reading responses - I am sure someone will know the reason.

Hi Adri,

Welcome to BirdForum!

The pink colour is from carotenoid pigments that they pick up in their diet; it transfers from the stomach to the preen oil gland, and from there is applied to the feathers, staining them pink.

With gulls it is most likely to be from shrimps, but it could also be from plant carotenoids: the same pigment is present in e.g. red pepper (Capsicum). So a gull could be eating red pepper on rubbish tips, or left-overs of take-away meals that people drop in the street.

The red in some finches, e.g. Crossbills, is also from these pigments in their diet. Why only the males develop it, I don't know, maybe the females digest (break down) the pigment.

Michael

Hi Michael,

I know that some birds (flamingo's) have enzymes that synthesize carotenoïdes from plants and animals to the rose colours in the feathers. In zoos where these birds doesn't get their 'natural' food they become special preparations to hold their colour.

So with these gulls it seems a different process: they spread out the rose oil gland about the white (only the white?) feathers.

If so, why only a few Black-headed gulls (has it something to do with the active hormones during the breeding-season?) and the most Little Gulls.

Of course I asked some birders in Holland too, but the opinions are divided. A pigment-expert has doubts about the theory of food and oil gland. In his opinion most birds have melaninen in the feathers which are not sensitive for food (except the carotenoïdes of ibis, flamingo, canary, some finches etc.). Perhaps that some very vital birds (hormones) 'produces'a clear colour.

I hope I can find a scientific founding of your and others opinion.

Thanks again,
Adri

I was in Murcia, Southern Spay a few weeks ago and one of the highlights was large numbers of Slender-billed Gull, most of which had vivid pink flushes.

There were Flamingo's too, ranging from "pied" youngsters to pink adults - but it was the gulls that looked the best!

I have no idea why they go pink - I'll leave that to the scientists, but I sure enjoyed the results!

I don't know if this helps, it's sort of relevant.

A friend of mine studying to be a surgeon once told me that when dissecting corpses or observing operations a child's intestines would be pink-flesh coloured and an adult's especially old people would be bright orange.

This is a result of years of carrot staining!

Have a lovely brunch!

tom mckinney said:

I don't know if this helps, it's sort of relevant.

A friend of mine studying to be a surgeon once told me that when dissecting corpses or observing operations a child's intestines would be pink-flesh coloured and an adult's especially old people would be bright orange.

This is a result of years of carrot staining!

Have a lovely brunch!

Click to expand...

Hi Tom,
I think your friend's observation has more to do with intestinal submucosal blood flow than carotenoid pigment staining. Intestinal perfusion is better in kids & young adults than in older folk.The cells lining the intestine (enterocytes) are replaced every 2-3 days thus making pigment staining unlikely. Besides there are other pigments (biliary pigments) which have much greater staining potential than carrots.............. I can't believe I'm sitting typing this over my lunch break- gross!!! :eek!:

Thanks for that Steve ... I think ...

eeeeeuuuuuuurrrrgggggghghhhhhhh

tom mckinney said:

I don't know if this helps, it's sort of relevant.

A friend of mine studying to be a surgeon once told me that when dissecting corpses or observing operations a child's intestines would be pink-flesh coloured and an adult's especially old people would be bright orange.

This is a result of years of carrot staining!

Have a lovely brunch!

Click to expand...

Tom i think your friend is extracting the urine!:'D

bert said:

Tom i think your friend is extracting the urine!:'D

Click to expand...

No I'm sure he said they were post mortems

tom mckinney said:

No I'm sure he said they were post mortems

Click to expand...

That's this thread killed off!!

:eek!: Errr . . . back to the subject, pink gulls . . .

What I'd understood is that the shrimps necessary in their diet to produce the pink pigment are hard for gulls to catch, and that therefore, a gull which is able to catch them and turn pink is demonstrating that it is a very fit individual, and therefore a good mating partner.

Different gull species have different feeding techniques, and the suggestion is that Little Gulls and Slender-billed Gulls (and Ross's Gulls, and Roseate Terns, of course) have evolved better techniques for catching them.

Of course if a Black-headed Gull can learn to cheat by going down to the tip and looking for red peppers . . . :-O

Perhaps it would be worth experimenting - find an individual come-to-food-tame BHG you can recognise, and make sure you give it some lightly cooked red pepper every day, and see if it turns pink, with others in the flock staying white

Michael

Why would a female gull want a mate who is good at catching shrimps in preference to other fish? What's the biological advantage?

Jason

Hi Jason,

The suggestion is, that if he's capable of catching shrimps, then he can get anything. Means he's a very good catcher overall, and the family won't go hungry during bad weather, when everything gets difficult to catch.

Michael

Astaxanthin is responsible for the pink plumage flush in Franklin's and Ring-billed gulls
Kevin J. McGraw1,3 and Lisa S. Hardy2

ABSTRACT. Carotenoid pigments produce the red, orange, and yellow plumage of many birds. Carotenoid-containing feathers are typically rich in color and displayed by all adult members of the species. In many gulls and terns, however, an unusual light pink coloring (or flush) to the normally white plumage can be found in highly variable proportions within and across populations. The carotenoid basis of plumage flush was determined in an Elegant Tern (Sterna elegans; Hudon and Brush 1990), but it is not clear if all larids use this same mechanism for pink plumage coloration. We examined the carotenoid content of pink feathers in Franklin's (Larus pipixcan) and Ring-billed (Larus delawarensis) gulls and found that a single carotenoid—astaxanthin—was present. Astaxanthin was primarily responsible for the flush in Elegant Terns as well, but was accompanied by other carotenoids (e.g., canthaxanthin and zeaxanthin), as is typical of most astaxanthin-containing bird feathers. In both gull and tern species, carotenoids were contained within feathers and did not occur on the plumage surface in preen oil, as some have previously speculated. We hypothesize that some gulls turn pink because they acquire unusually high amounts of astaxanthin in their diets at the time of feather growth. It is tempting to link the increase in sightings of pink Ring-billed Gulls since the late 1990s with the introduction of pure, synthetic astaxanthin to the diets of hatchery-raised salmon.

http://www.blackwell-synergy.com/doi/abs/10.1111/j.1557-9263.2006.00008.x

In breeding plumage, and sometimes in nonbreeding plumage as well, the Franklin's Gull often shows a rosy pink cast (rarely salmon) on its chest and abdomen. This color is most apparent on the shafts and bases of its feathers. The color fades as the breeding season progresses as the pigment is broken down by sunlight.

http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Franklins_Gull_dtl.html