projectile pooping

[John Chardine]

I've been trying for 8 seasons to capture penguin chicks pooping because the distance they achieve is worthy of the Olympic Games! Well I have failed thus far but today I got lucky with nesting ospreys. Take a look at the image. The chick (cloaca visible through the nest sticks) has just been awarded the gold medal and has produced a prodigious curl of uric acid to the right. Unfortunately I cut off a portion of the production so there goes the image critique. I have had several laughs trying to come up with a caption for the parent, considering her/his expression (embarrassment?!). "What the %#$@ was that?" comes to mind. Anyway I digress. So why do chicks of some species expend considerable energy making sure they don't foul their nest while others use the blanco excremento as a cement to bind the nest material together? Let's have a collective think.

[Sharna Lee]

OMG! I laughed so hard at the title of this! Not only that but I had to drag my husband and daughter in here to look at this.
I don't know what else to say. Excellent capture? hahahaha

And I have NOOO Clue why? k. hehehe

Sharna

[Daniel Cadieux]

I will guess it is to keep the nest clean. Imagine all the "stink" it would raise if all that would accumulate day after day after day (not to mention health reasons to be sitting in it)!! I've observed smaller birds at nest locations where the parents grab the fecal sac directly out of the, um, rear as it comes out and then fly away to deposit it elsewhere. I think birds of prey may be ill-equipped to do this with their hooked bills therefore the young ones have developped the ability to shoot it straight out of the nest :-) Am I close to the answer??

[Axel Hildebrandt]

Considering that most birds don't have a developed sense of smell my guess is that they might try to avoid sitting in their droppings. The plumage would look pretty messy after a while which can't be good, maybe it would even be a breeding ground for parasites.

[Anita Rakestraw]

She may be thinking "Wow, I've got a prodigy here!!" LOL! I would think the behavior is an instinct related to health preservation, but have no idea in that event why not all birds practice it. In some species, the parents do clean the nests out, I believe. Fun pic, and that parent's expression is hilarious!

[Barry Goggin]

I dont know why some birds exhibit projectile excretion and others dont.
I wondered if it is related to the consistency of the fluid which may in turn depend on diet. However it seems that parrot species vary in whether they show projectile excretion or not and their diet does not seem to be significantly varied between those who do and those who dont.
However you mentioned penguins and photographing them like this. It turns out that there is a paper on projectile defecation in penguins which used some "spot-on photographs" to determine pressures needed to expel.
Though the pressures generated are quite high, they say that they are not energetically costly. The paper makes for quite a funny read especially the diagram of the penguin in action!
http://www.scribd.com/doc/2472988/Pressures-Produced-when-Penguins-Poo

"With all of these parameters measured, we calculated that fully grown penguins generate pressures of around 10kPa(77mmHg) to expel watery material and 60kPa(450mmHg) to expel material of higher viscosity similar to that of olive oil."

Still I dont see an answer as to why it occurs in some birds and not others.

Great photo. Maybe you should submit it to the authors for some calculations!

[Julie Kenward]

This looks like the expression of a first time human parent when they are about to pull down that first "muddy" diaper... What a capture, John! I noticed you didn't say whether you got any of that on you or not...

[Maxis Gamez]

You don't poo where you eat. That's what my mama told me.... :)

[Robert Amoruso]

Stay clear of wood storks and cormorants if pop worries you.

[John Chardine]

Thanks Barry- I use that paper in my penguin lectures. I hope folks took the time to look at it!

Maxis- But some birds do poop where they eat. That's essentially the question.

Overall, here's my view and roll-up of the responses so far. Nest sanitation is important, especially for cavity nesters. Many passerine chicks produce a fecal sac- the white uric acid which is the nitrogenous waste part (the "pee") and the faeces- nicely wrapped up in a thin, membranous sac, which the parents dutifully remove from the nest and drop some distance from it so that predators so not see the white marks.

This last point I think is driving the issue in many species. White flashes of bird poop around a nest attract predators so many birds make sure it goes over the side. Some birds that nest in precarious situations like on cliffs may benefit from uric acid and faeces around the nest to bind the contents together and make the platform more stable- I'm having trouble right now thinking of a specific example, except maybe kittiwakes.

[Amy DeStefanis]

Wow - for the lucky folks who get to measure velocity and viscosity ("not quite olive oil yet"), they probably have an interesting time answering the question: So what do YOU do for a living?

:)

Priceless expression on the proud parent's face!