Date: 8/6/25 5:07 pm From: ed pandolfino via groups.io <erpfromca...> Subject: Re: [CALBIRDS] Pied-billed Grebe sinking behavior references?
A plug for BOW...
Anyone with even a passing interest in the biology, ecology, or behavior of birds should have a subscription to Birds of the World. At $49/year, a bargain at twice the price. https://birdsoftheworld.org/bow/subscribe Ed PandolfinoSacramento, CA
On Wednesday, August 6, 2025 at 04:09:23 PM PDT, Zac Denning via groups.io <zdenning1...> wrote:
Hi Joel,
Grebes have fine control over their buoyancy. They can sink at will by squeezing air out of their plumage (by flattening their feathers) as well as by expelling air from their internal air sacs. According to Birds of the World, the structure of their contour feathers includes coiled barbules that may serve to trap water and this may also give them a sleeker, more hydrodynamic profile, creating less turbulence as they glide through the water.Â
These adaptations allow them to float or sink to varying depths with ease. Unlike ducks, they don’t have to propel themselves at speed to keep from popping back up to the surface.
If you have a Birds Of The World subscription, this is covered for Pied-billed Grebe under Behavior > Locomotion > Swimming and Diving:Â https://birdsoftheworld.org/bow/species/pibgre/cur/behavior Zac DenningAlbany, CA
On Wed, Aug 6, 2025 at 11:51 AM wagtail1997 via groups.io <orcorba...> wrote:
Group,Mason Regional Park (Irvine, Orange County, CA) has a high density of Pied-billed Grebes right now. At least 3 of the 14 are showing quick sinking behavior. I've studied that for the last two weeks and come up with videos on the behavior, analysis of the sinking, a summary of possible mechanisms, ecology, and more. All that is missing is to actually find a scientific paper on the behavior, even after doing some online searches for such studies. Anyone have a reference that I can add to my show notes? The Grebe's legs and feet have a role in the late stages of the sinking. The head behavior is interesting and lags the submersion of the rest of the body.  I raise more questions than I can answer about the behavior.  https://youtu.be/v95FQgHPxq8 Â
Joel WeintraubIrvine Ca
