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Herring gull eats sea star, and other tales of larid gastronomy

The views expressed are those of the author and are not necessarily those of Scientific American.


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There is grandeur in this view of life. Photo by Darren Naish.

My photography skills – if I can call them that – are pretty atrocious. While on a break in Wales recently, I managed to photograph a sequence in which a Herring gull Larus argentatus (one of our most frequently encountered gulls) swallowed a Common sea star Asterias rubens. Yeah, that’s right, get into the habit of calling them sea stars – makes you feel so much better than stupid old ‘starfish’. Of course, gulls swallow sea stars on regular occasion and this image isn’t (so google reveals) at all remarkable. Google ‘gull eating starfish’ for yourself if you want to see far superior images (many of which are a bit gross in showing gulls swallowing unfeasibly big sea stars, some of which get stuck in the birds’ gullets and remain there for a while as an unsightly lump).

Western gull # 1 eating a Pisaster. Western gull # 2 looks on, interested. Photo by Minette Layne, licensed under Creative Commons Attribution 2.0 Generic license.

Large gulls are in fact important sea star predators, so much so that they might have influenced their evolution: this 2013 conference abstract describes how colour change observed during the ontogeny of the Pacific sea star Pisaster ochraceus might be an adaptational response to gull predation [adjacent image by Minette Layne]. However, the importance of gulls as sea star predators is apparently not well studied and there are some indications (I’m going from this 2009 poster by P. Monteforte and colleagues on Western gull L. occidentalis predation on Pisaster species) that gull predation is – in some places – having a negative impact on sea star populations. So, gull increase could conceivably result in sea star decline. Cue discussion of trophic cascades and so on: white-headed gulls certainly have many resources they can switch to when sea stars aren’t around, so it’s not as if they rely on these echinoderms as a prey base; they merely exploit them when available.

Here it’s worth saying that, while white-headed gulls of several species (Herring gulls in particular) are frequently said to be increasing exponentially in population size, this in fact only applies to urban populations: the overall populations of these birds are plummeting. Yes, even for the Herring gull, the UK population of which is currently at its lowest level since recording began in 1969/70 (see graph below, from the Joint Nature Conservation Committee’s Herring gull page). Believe it or don’t, it’s now a Red List species.

Trends in abundance of the UK Herring gull population, 1986-2011, from Joint Nature Conservation Committee. A huge surge in the number of urban-breeding gulls masks the fact that the population is declining overall.

Back to sea stars… sometimes, gulls swallow the sea stars whole, as shown above, but on other occasions they shake them so that they break to bits (Wilkie 2010). As you may know, being broken into bits isn’t the end of things for a sea star, since it’s capable of autotomy at the base of each arm. Not only can the animal regrow the lost arm, the arm itself can survive and produce a new individual (hence explaining why the tearing of invasive sea stars in half to ‘kill’ them is probably not a good idea).

A Sony Ericsson W610i swallowed (and later regurgitated) by a gull, from Camphuysen et al. (2008).

The feeding habits of Herring gulls remind me of the Tet Zoo article I wrote on this very topic back in 2009 (it’s here). On that occasion, study at a nesting colony revealed the swallowing by gulls of toy soldiers, plastic and metallic food waste, discarded medals, and a mobile phone (Camphuysen et al. 2008). And here’s something that concerns one of my favourite subjects: ‘unexpected’ ingestion of plants by a predator. It turns out that white-headed gulls of some species – you know, gulls… those big, predatory birds that eat fish, crustaceans, echinoderms and so on – eat enough plant material to act as locally important dispersers of seeds (in this case of madders [Rubia species]) (Nogales et al. 2001).

Gulls deserve more respect. They are not big white sky-rats.

For previous Tet Zoo articles on gulls and other seabirds, see…

Refs – -

Camphuysen, C.J., Boekhout, S., Gronert, A., Hunt, V., van Nus, T. & Ouwehand, J. 2008. Bizarre prey items: odd food choices in herring gulls and lesser black-backed gulls at Texel. Sula 21, 49-61.

Nogales, M., Medina, F. M., Quilis, V. & González-Rodríguez, M. 2001. Ecological and biogeographical implications of Yellow-Legged Gulls (Larus cachinnans Pallas) as seed dispersers of Rubia fruticosa Ait. (Rubiaceae) in the Canary Islands. Journal of Biogeography 28, 1137-1145.

Wilkie, I. C. 2010. Do gulls benefit from the starfish autotomy response? Marine Biodiversity Records 3, e12 doi:10.1017/S1755267209990480.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Halbred 3:52 pm 05/2/2013

    How does the lone sea star arm sustain itself while it regrows…a body? It can’t eat, right?

    Link to this
  2. 2. naishd 4:25 pm 05/2/2013

    Hey, I don’t do echinoderms. Anyone who knows what they’re talking about wanna answer?

    Darren

    Link to this
  3. 3. squidboy6 5:05 pm 05/2/2013

    I’ve seen a lot of otters eating “starfish” which is usually a way to limit competitors. If the starfish are gravid then there’s some nutrition but otherwise they’re more filling and less taste… a lot like some beers!

    Other echinoderms like sea cucumbers eviscerate to put off predators then regenerate new organs. They must do this by remobilizing proteins from their somatic regions. Starfish probably do the same.

    I have seen starfish that regenerated portions of their arms and oral disks and they’re greatly reduced in size so they have to eat to grow back to their former sizes. I haven’t seen any formal studies but a portion of the disk and water-vascular system is needed in the broken part – there’s a limit to this.

    I have never seen this in brittle stars but I have seen brittle starts that have lost most of their appendages and they survived a long time. As long as they can eat they seem to be capable of regenerating and surviving. Plus I think they can get really old too. S. franciscanus (red urchins) have been dated to be 200 yrs old. from the Pacific NorthWest.

    Link to this
  4. 4. Neil K. 12:35 am 05/3/2013

    This is from a dated reference but one of the few detailed studies of whole-body regeneration (as opposed to single-arm autotomy or regeneration)

    “It is remarkable that a section of a ray less than 1 inch long will live indefinitely with the nerve cord severed and the water tube cut off from the natural supply. The behavior of the segment indicates that the nervous system functions normally and that the tube feet carry out their activities as usual … It is probable that organic matter is absorbed through the softer tissues exposed to the water in sufficient quantity to effect growth”

    CH Edmondson 1935. Autotomy and regeneration in Hawaiian starfishes. Bernice P. Bishop Museum Occasional Papers, 11(8).

    Available online as a pdf at the Bishop Museum website for those curious enough to track it down.

    Link to this
  5. 5. Dartian 12:54 am 05/3/2013

    Heh, if the discussion continues like this, we’ll get the first(?) Tet Zoo comments thread where we won’t be talking about tetrapods – or even vertebrates! :)

    Gulls deserve more respect. They are not big white sky-rats.

    I agree, but IMO rats deserve more respect too. They are not big furry cockroaches. ;)

    Link to this
  6. 6. Andreas Johansson 1:23 am 05/3/2013

    Why exactly is “sea star” so much better than “starfish”? I mean, they’re not fish, but still less are they stars …

    Link to this
  7. 7. BrianL 7:41 am 05/3/2013

    Why is that gull populations seem to be plumetting, except in cities? Are they running out of food? Are their nests being predated upon by, say, foxes? Surely, large white headed gulls do not feature on the diet of many predators as adults?

    Link to this
  8. 8. David Marjanović 10:23 am 05/4/2013

    Ah, good I’m still logged in at home, because in the museum I was logged out and can’t log in again.

    Other echinoderms like sea cucumbers eviscerate

    I thought only sea cucumbers do that?

    Link to this
  9. 9. AlexanderBerg 7:09 pm 05/5/2013

    New sub-blog: Pentapod Gastronomy?

    Link to this
  10. 10. naishd 4:49 am 05/6/2013

    Pleased to see this article picked up by Boing Boing: Gull eats starfish, auditions for role as LOL animal.

    Darren

    Link to this
  11. 11. Mark Robinson 4:54 am 05/7/2013

    They are not big white sky-rats
    I agree, that would be pigeons. Gulls are more like dogs with pica (not Pica!).

    There’s even a scent that you can buy – http://www.zomgsmellsshop.com/seagull-eating-a-starfish-1/

    Link to this
  12. 12. David Marjanović 10:26 am 05/7/2013

    Pleased to see this article picked up by Boing Boing:

    Somebody please comment there on the outrageously stupid claim that “the story” of Biston betularia was “faked”. It’s currently the last comment.

    Link to this

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