Welcome to another article in the ‘over-enthusiastic swallowing’ series. As was the case with the previous article (the one on Mushu the pet bearded dragon), this one doesn’t involve the death of the animal(s) concerned. In fact – so far as we can tell – the creature(s) that did the swallowing didn’t suffer any ill effects from its/their behaviour at all. The creatures concerned are gulls: specifically, Herring gulls Larus argentatus and Lesser black-backed gulls L. fuscus [adjacent image from Camphuysen et al. (2008); read on].
Camphuysen et al. (2008) were interested in finding out what the breeding gulls of Texel, in the Netherlands, were eating, so they collected and studied the regurgitated pellets that the gulls produced. They analysed 3876 pellets (the Dutch word ‘voedselmonsters’ is used for the analysed objects: is this really synonymous with ‘pellet’?). By far the majority of pellets contained the remains of ‘expected’ prey. That is, the remains of bivalves, crustaceans and fish, and it really should be emphasised that virtually all of the pellet contents represented prey of this sort. However…
Gulls are highly opportunistic, highly adaptable birds that don’t seem shy about ‘experimenting’ with novel or risky prey, and the study also revealed a really interesting list of anomalies. Evidence for the ingestion of berries, grapes*, fly larvae and snails was recorded. One juvenile Lesser black-backed gull had been fed rat-tailed maggots by its parents, but these evidently disagreed with it and it regurgitated them intact (Camphuysen et al. 2008). Potentially less harmless were the plastic or metallic food-wrappers eaten by gulls, including cheese and sausage wrappers, metallic tubes and bottle tops [some shown here, from Camphuysen et al. (2008)]. Bits of elastic, foil and paper were also discovered in some pellets, as were balloons. As is hopefully well known, marine birds are routinely eaten huge quantities of floating plastic these days, and are dying as a result. This is not a trivial problem: there are indications that some populations, and probably some species, are being seriously affected by this.
* Surprisingly, some gull species ingest enough plant material to act as important dispersers of seeds. In the Canary archipelago, for example, Nogales et al. (2001) concluded that Caspian/Yellow-legged gulls L. cachinnans may well be important distributors of endemic Rubia species.
But then we get to the really weird stuff: in a study as large as this, quite a few anomalies were found. One gull had swallowed the legs of a small plastic doll [shown below; from Camphuysen et al. (2008)]. Another one ate a plastic squid-like fishing decoy (which is not so surprising, as the object looks like a real squid). 16 small army figures had been swallowed by one gull [shown here; from Camphuysen et al. (2008)], hence the reference to a ‘whole army’ in the article’s title (note, however, that the toy soldiers were little ones, not the more typical 50-mm-tall ones we’re used to). Another gull had eaten a whole medal (still with complete ribbon attached: it’s shown above), and another one had swallowed a whole mobile phone [shown at top] (Camphuysen et al. 2008). Funnily enough, the phone – a Sony Ericsson W610i – is exactly the same (now quite dated) phone that I use, and if you want confirmation look at the photo here.
The fact that large gulls will eat incredible and ridiculous items such as these is well known among gull workers. As has been mentioned here at Tet Zoo a few times, a brand-new bar of soap, still with label attached, it also on record as having been swallowed by a gull (thanks Jerzy). I’d be interested in hearing about additional bizarre anomalies – please do mention any that you’ve heard of.
I’m indebted to C. J. Hazevoet for bringing Camphuysen et al. (2008) to my attention.
For previous articles in the ‘over-enthusiastic swallowing’ series see…
- Roadrunner tries to eat horned lizard. Splits neck open. Dies.
- Snake 195 mm long eats centipede 140 mm long. Centipede too big. Snake dies.
- Perentie tries to swallow echidna. Echidna too spiky, Perentie gets horribly injured. Dies.
- Heron tries to swallow giant lamprey. Chokes. Dies. Second heron tries same trick. Also chokes. Also dies.
- Mushu the dragon eats a large toy lizard. Toy lizard passes through digestive tract. Mushu lives!
And for articles on gulls and their taxonomy, variation and phylogeny, see…
- Why the Lion Grew Its Mane, a book review
- To the Sahara in quest of dinosaurs (living and extinct)
- Happy 2009, from the gulls
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.