I love it when you find a paper that precisely answers a question we were thinking about today - how much like a natural egg does a dummy egg have to look like so the gull will accept it?

[sarahdalgulls@ecoevo.social]

I love it when you find a paper that precisely answers a question we were thinking about today - how much like a natural egg does a dummy egg have to look like so the gull will accept it?

Answer - they'll even accept a bright red cube if it's approximately egg size, which I can vouch for, having seen Herring gulls incubating vaguely spherical rocks, golf balls, and on one occasion, a head from a Barbie doll

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(pmc.ncbi.nlm.nih.gov)

#Gulls #Ornithology

[processparsnip@mastodon.ie]

@sarahdalgulls that... that's real cute. What are these gulls even doing.

[nev@flipping.rocks]

@sarahdalgulls related: https://www.researchgate.net/publication/326574850_Roly-Uoly_Egg_Sacs_Isopods_Used_as_Replacement_Egg_Sacs_by_the_Wolf_Spider_Pardosa_valens_Araneae_Lycosidae

[cccpresser@chaos.social]

@sarahdalgulls thank you for this post. This is the content that makes fediverse fun and interesting ️

[sarahdalgulls@ecoevo.social]

@nev oh wow! brilliant!

[sarahdalgulls@ecoevo.social]

@ProcessParsnip eggs is eggs!

[sarahdalgulls@ecoevo.social]

I have just had a look at the original research on gulls and their eggs, Niko Tinbergen's 1953 study The Herring Gull's World. He found that giving the gulls a choice between Yellow and natural, Blue and natural or Red and natural coloured eggs, they didn't show preference except for Red or Natural - then they favoured the natural coloured eggs

[neckspike@indiepocalypse.social]

@sarahdalgulls a lot of birds are not good at identifying things that are not their eggs. Is it vaguely the right size? is it in my nest? must be my egg, lemme sit.

Ratsnakes are also bad at identifying eggs. If it's kinda round and warm and possibly smells like bird butt it's delicious egg and they will swallow it.

[sarahdalgulls@ecoevo.social]

also: "Influence of size... the giant egg was chosen 6 times whereas the normal [sized] egg was never taken. All birds which were given the large egg became very excited and made frantic attempts to cover it"

[sarahdalgulls@ecoevo.social]

Tinbergen was the first to study animal behaviour as a science - ethology - with his study of gull behaviours, and the book is probably a little outdated now in that regard, but it has very readable descriptions of Gull behaviours. It was certainly the book I read that made me realise gulls were more than just angry squaking chip thieves!

You can loan it at Internet Archive -

https://archive.org/details/herringgullsworl0000tinb_o4l0

[neckspike@indiepocalypse.social]

@sarahdalgulls "Wow look at what I made!"

[processparsnip@mastodon.ie]

@sarahdalgulls absolutely *cackling*

[amateurexpert@flipping.rocks]

@neckspike @sarahdalgulls

see, this is the kind of very important bird discourse I came here for.

[steve@social.coop]

@sarahdalgulls Instinct is powerful, but not very specific.