Today we have another science-and-photo feature by Bruce Lyon, a professor of ecology and evolutionary biology at the University of California at Santa Cruz. This time the subject is not coots but grebes. (Baby grebes are about the cutest waterfowl going.) Bruce’s notes are indented, and the photos are great!
The wetlands where we study American coots in central British Columbia, Canada are also packed with lots of other species of waterbirds. The bird densities are very high, which makes the wetlands feel incredibly birdy and active. The floating blinds we use in our coot study are also great for getting up close and personal with these other water birds—a bird photographer’s dream. Today I will highlight the grebes that nest on our study wetlands.
Below: Eared Grebes (Podiceps nigricollis) are gorgeous birds with their yellow ear tufts and bright red eyes. This species also breeds in Eurasia, where it is known as the Black-necked Grebe. They nest in colonies ranging from a dozen to up to hundreds of pairs, and nests are often very close to each other—1 or 2 meters. The photo below shows a nest in low density colony where the birds were spread out. The nests are floating platforms of wet vegetation. Whenever the birds leave the nest they hide their eggs by covering them with the nest material. The pink flowers in the photo are aquatic smartweed (or knotweed) flowers in the buckwheat family (Polygonacea).
Below: When the eggs hatch, the entire grebe family leaves the nesting colony and the chicks are ferried around on their parents’ back like royalty. The family does not return to the nesting area but instead roams widely on the wetland. Baby grebes have striking plumage patterns and are apparently called ‘stripe-heads’. In addition to the stripy plumage, the chicks have bare patches of skin that can rapidly change from a pale flesh to a bright red color. The function of the plumage markings is not entirely clear, but in some species the bare patches seem to function both for begging for food and in signaling distress. When the chicks are hungry the patches are dull, and when they are not hungry they are bright red. Perhaps the skin patches provide an honest signal of chick hunger that lets the parents assess which chicks need the food the most.
Below: Typically one parent searches for food and brings it back to the floating restaurant.
Below: Another portrait of a parent carrying its chicks. Why grebes (and other birds like loons and some swans) carry their chicks is not entirely clear. I am currently working on a short note about the topic for a scientific journal. Some of the potential benefits of carrying chicks include: (1) brooding the chicks to keep them warm (the small–bodied chicks would loose a lot of heat if they were to swim on their own); (2) safety from predators (our wetlands lack predatory fish but carrying chicks might make them safer from aerial bird predators) and, finally, (3) carrying the chicks might allow the family to travel greater distances than would otherwise be possible (although ducks do not carry their kids and broods, some species seem to be able to travel pretty big distances—not Jerry’s ducks though!)
Below: A gorgeous Horned Grebe (Podiceps auritus). I only ever found one nesting pair of these birds at my study site—on a small isolated pond. Horned Grebes are very different from Eared Grebes in that they are fiercely territorial—only one pair per small wetland.
Below: The small wetland where I found the Horned Grebes.
Below: Another view of the Horned Grebe.
Below: The pair was busy building a nest while I watched them. They were fetching old reed stems as building material and often swam under water with the material. Grebes are excellent swimmers: they are foot-propelled divers and, like coots, have lobed rather than webbed feet. The feet are located very far back on the body, which is great for swimming but it sucks for walking: these birds can barely walk on land and even getting up on their nests seems like an ordeal.
Below: Red-necked Grebes (Podiceps grisegena) also nest on some of our wetlands. They too are territorial so we never get more than one pair per wetland. This species is also considerably larger than the other two species described above.
Below: Up periscope—a little stripe-head backrider sticks its head up to get a view. Dad, are we there yet?
Below: Both parents are carrying chicks so I guess they were taking a break from feeding. Note that both parents have the same colorful plumage—this pattern, and grebes specifically, played an important role in a big debate in evolutionary biology in the 1930s. Grebes (and many other birds) are interesting because they have dull winter plumage but both sexes then molt into a colorful garb for the breeding season. Julian Huxley, an evolutionary biologist famous for his role in the Modern Evolutionary Synthesis, studied courtship in Great Crested Grebes in Europe and came to the conclusion that sexual selection by mate choice could not explain the courtship and plumage patterns of grebes, or any organism for that matter. Darwin had proposed a mechanism of sexual selection that could explain ornamentation of both males and females—mutual mate choice by both sexes—but he then quickly ruled out the idea because he thought males were too randy to be picky about mates. It turns out that Darwin got this one wrong and sexual selection through mutual mate choice has now been clearly documented in lots of birds. This mechanism may explain the brightly colored males and females in grebes. Darwin was wrong on a minor point (mutual sexual selection) while Huxley was profoundly wrong on a key point (sexual selection by mate choice). Nonetheless, because he was such an influential figure, Huxley’s views pretty much stifled interest in sexual selection for some time.
Below: One parent offers food (a dragonfly larvae I think) while the other shakes a caddisfly larva to remove the protective house the larva has constructed around itself (the water flecks are from the shaken caddisfly). Caddisfly larvae are preferred prey items for both coots and grebes and it is easy to see when one has been captured because the birds have to vigorously shake the houses to extract the larva within.
Below: A caddisfly larva in its house (photo from the web).
Great pictures and story. Thanks for that.
Great photos!
Absolutely gorgeous! There is no shortage of pictures here that could go into Nat Geo, or other venue that celebrates wildlife photography.
Incredible! Love those red eyed grebes. A little scary looking, but they seem to be good parents.
How does one start a new thread? I would like Jerry’s reaction to this article from Science Magazine’s daily news:
http://www.sciencemag.org/news/2017/08/cold-snap-makes-lizards-evolve-just-few-months?utm_campaign=news_daily_2017-08-03&et_rid=291148098&et_cid=1474226
Only Jerry can post here, but he does appreciate readers’ suggestions. You can find his email address through Google or by clicking on the Research Interests link at the top of each post here.
Note that he receives an often overwhelming number of submissions; he can’t reply to all of them and suggests that readers not overload his inbox; if you ever have more than one topic to suggest, please put them all in a single email. (I forget what frequency he requested–once a week? Every other day? Anyway, you get the idea. 🙂 )
Make that first “suggests” a “requests.”
Lovely photos and thought-provoking text. I was intrigued by your comment that the pink patches on the young grebes could be honest signals about which one needs food. Normally this sort of honest signal would not be an evolutionarily stable strategy, because a baby with “cheater genes” (always signalling hunger) would be more likely to survive to adulthood. But the cheater’s brood, if it expressed the cheater’s genes, would likely be smaller than a brood of honest signalers. So it seems like it might be evolutionarily stable in this case….
I was wondering about cheaters too. Thanks for voicing it. I hope Dr Lyon can say something about it.
Why do you (Lou) think that a cheater’s brood would be smaller than a brood of honest signalers?
Because the brood would have lost the honest signals that allow the parents to distribute food evenly. Without those signals, perhaps the oldest chick would get everything.
Ah, yes. Of course. I was thinking you meant something else (fewer eggs, maybe). Thanks.
Glad you asked, mikeyc, I was wondering the same thing.
Great point. This is a big issue in the field of begging generally and the idea is somehow that these signals must have mechanisms to keep them from being cheated on. Put another way, parents should only pay attention to signals that cannot be bluffed. Folks have suggested that blood flow changes when the gut is full and perhaps that is what is going on with these signals but I am 100% clear on exactly how it works.
But if cheater genes cause their bearers’ broods to be smaller than non-cheater’s broods, this automatically keeps such signals honest enough.
Yes and no. The whole idea of Triver’s parent offspring conflict theory is that traits that benefit kids, but reduce parental fitness, might be favored. So in theory we might see such traits evolve. There are putative examples of such traits in nature but the evolutionary dynamics get tough to think about and almost cause my brain to melt. One neat example are sib-killing wasps. Sib-killer larvae basically execute any other larvae that share the host with it. Sib-killer species have a clutch size of one (which makes sense because any dopey mother than lays more than one egg is basically set up siblicide. What is interesting is that across species, there is a gap in clutch size (number eggs a female lays per host) and no species with clutch sizes of two or three. The argument is that these clutch sizes are in the range where a sib-killing trait can evolve—the benefits to the killer outweigh the lost fitness of killing a sibling. At much larger clutch sizes the idea is that a sib-killer would exterminate too many relatives, and too much indirect fitness. Kin selection puts the brakes on sib-killing evolving at large clutch sizes.
But isn’t this kind of signaling a special situation? Cheaters are going to be the victims of their kids’ cheating, and so they will raise smaller broods. That gene shouldn’t spread through the population, right?
This has been a debate. Initially Richard Alexander made this same point but further theory clarified things (sort of). A couple of points. First, I think that one way to think about this is that the conflict is not really between individual parents and individual offspring, but a conflict between two life history stages—-parent and kid. Second, another way to think about it is whether a mutant gene that crops up in a kid that helps the kid but harms the parents would spread evolutionarily. Again theory suggests yes, but the conditions are more stringent than Trivers realized, in part due to the precise point that you (and Alexander raise). Interestingly, I think that once the gene spreads, there really is not much of a conflict anymore—-success as a kid is a bit higher while success as a parent is slightly decreased, but this applies to everybody.
Very interesting, thanks for the history!
Another great post! And this intrigued me: “Darwin was wrong on a minor point (mutual sexual selection) while Huxley was profoundly wrong on a key point (sexual selection by mate choice). Nonetheless, because he was such an influential figure, Huxley’s views pretty much stifled interest in sexual selection for some time”
Many great posts on WEIT, including this one, produce an expanding network of questions I’d like the answer to, but I suppose often the answers are unknown or there’s a divided opinion.
In attempting to find out out about Julian Huxley profound wrongness in, I assume, *Courtship Habits of the Great Crested Grebe [1914]*, I came across this interesting article entitled *In retrospect: The Courtship Habits of the Great Crested Grebe* wherein Michael Brooke “reappraises Julian Huxley’s pioneering classic of animal behaviour on its centenary”:
http://www.nature.com/nature/journal/v513/n7519/full/513484a.html
I am none the wiser
I’ll keep looking of course 🙂
I didn’t know Huxley differed with Darwin on sexual selection. It is also the case that Wallace strongly rejected the whole idea and his arguments were very influential as well. I don’t know if Darwin had much of any support at the time from biologists. One reason for the rejection seems to have been the Victorian notions about the proper roles of males and females in society.
Thanks for the link– that was an interesting article. As you note, it points out that Huxley poured water on the idea of sexual selection but did not really provide details. My information comes from a great book on the history of ornithology: Ten thousand birds: ornithology since Darwin (by Birkhead, Wimpenny and Montgomerie). It covers the big ideas and main players of ornithology over the past century which includes many big ideas in ecology, evolution and behavior. For anybody interested in bird biology I highly recommend this book (and it is not expensive). One book review called it riveting. The book points out that Huxley originally embraced female choice but then moved away from that idea, and from sexual selection more generally as well. Apparently he embraced the idea of group selection and correctly realized that sexual selection does not work for the good of the group. So in reality, Huxley screwed up on two big ideas not just one: sexual selection and group selection. At least he studied nice birds—-the grebes. The information in the book often came from sources other than publications, such as letters, etc…
Gorgeous photos and very interesting, as always. Most enjoyable!
Wonderful pics and information. Thanks!
Yes the male Grebes are beautiful, but not as much so as male harlequin ducks or male wood ducks. No worries though, cause they put the ugly emu to shame…
Fabulous photos and info! I envy your fieldwork experiences.
Well, on second thought, maybe not. It can’t be that pleasant mucking through swamps all the time. Wonderful bird company though!
Au contraire, mucking around the swamps in central BC is about as good as it gets—-often the weather is nice, the natural history is non-stop and the biting insects are pretty much absent.
That’s true, the insects are one of the best parts about BC. I just spent a couple weeks on the east coast and had forgotten about how annoying biting flies and clouds of mosquitos can be.
Thank you for the grebe photos and informative commentary. Also, helpful perspective on parent-offspring conflict, sexual selection, etc.
Love the stripey periscope 🙂
Great photos and great biology! Thank you so much.
We see all these species here in SW MI, though only the Horned is common. Do you not get many Pied-billeds where you are in BC?
Looking at the distribution map, Pied-bills breed in southern BC. I used to watch them during my Michigan days in the Muskegon area.
Some of the best birding in MI–Muskegon Waste Water!
https://www.google.com/maps/uv?hl=en&pb=!1s0x88196e288448665b:0x5132cdcbe301e51!2m22!2m2!1i80!2i80!3m1!2i20!16m16!1b1!2m2!1m1!1e1!2m2!1m1!1e3!2m2!1m1!1e5!2m2!1m1!1e4!2m2!1m1!1e6!3m1!7e115!4shttp://muskegoncountywastewatertreatment.com/598/!5smuskegon+wastewater
(Sorry for the long url–too lazy to shorten it.)
Yes, I remember that place it was considered experimental in 1970s, as I recall. I’m happy to see it seems to have worked out well. I imagine the techniques used to handle yucky H2O here are being replicated elsewhere.
I hope so! From its literature and website it’s clear that it was designed to be an experiment and ultimately an example to follow, and it is indeed most successful. I’ve not run into similar operations elsewhere, though. That’s not really saying much, as I haven’t gone looking for them, except for the fact that waste-water treatment sites are often great for birding, so I’ve seen quite of few of the more traditional sorts.
Remembering back now, I think their claim to fame was that they used the local sandy soils and sub soils as filters and allowed the semi-clean water with lots of included nutrients to irrigate crops. It’s a little like using liquid manure. Something like that.
Yes. I liked their old website better, but there’s a brief summary of the operation here (not that you need it, but in case anyone else is interested):
http://muskegoncountywastewatertreatment.com/about-us/overview/
I’m just thrilled that they’ve always let birders in. You’d think they’d be too worried about potential liability, but we’re allowed to drive around the huge lagoons on the berms surrounding them, and through the fields of settling cells and some of the crops. Tremendous opportunity.
Enjoyed these and comments. Thanks.