FEMALE PLOVERCREST Stephanoxis lalandi TRAPPED IN
CATERPILLAR SILK - A SHORT NOTE
Paul Smith
The Plovercrest Stephanoxis lalandi is an Atlantic Forest Endemic hummingbird (Brooks et al 1993) restricted to southern Brazil, eastern Paraguay and extreme north-eastern Argentina (Monroe & Sibley 1997). It is considered uncommon in humid forest areas of Paraguay (Clay & del Castillo 2004) where it occurs mainly in the Alto Paraná ornithogeographic region of the country as defined by Hayes (1995), approximating to the eastern and southeastern Orient of Paraguay.
During fieldwork at PROCOSARA, Parque Nacional San Rafael, Departamento Itapúa, southern Paraguay on 17 February 2006 a distressed female Plovercrest Stephanoxis lalandi was found fluttering helplessly on the ground. The right wing and tail of the bird was entangled in a long strand of silk the other end of which was attached to a small unidentified sapling c10cm high. The leaves of the sapling bore the characteristic holes of the recent presence of a feeding caterpillar and a quick search of the immediate surroundings revealed what was presumably the other end of the silk, broken and dangling from a leaf bearing similar feeding holes. The absence of any visible broken spiderwebs in the area and the fact that the bird was bound in an isolated area of its body suggest that the caterpillar silk was indeed responsible for restraining as bird - a bird entering a spiderweb with such a force as to completely obliterate it would presumably do so head first.
In the Atlantic forest of Paraguay several families of caterpillar eg Geometridae suspend themselves by strands of silk as a means of escaping predators (Harold Greeney pers-comm.). The hummingbird did not possess the strength to break the strand alone and appeared tired, but once the silk was removed from its wings and tail manually it was soon able to fly away, apparently unaffected by its ordeal.
Though there are several records of hummingbirds (Graham 1997, McKenzie 1991) and other small birds (Hanmer & Dudley, Heck & Heck 2001 1988) becoming snared in spiderwebs, this appears to be the first published record of a bird being inadvertently trapped in caterpillar silk.
REFERENCES:
1.Brooks TM, Tobias J, Balmford A 1999. Deforestation and Bird Extinctions in the Atlantic Forest. Animal Conservation 2: p211-222.
2.Clay RP, del Castillo H 2004. Annotated Checklist of the Birds of Paraguay. Guyra Paraguay, Asunción.
3.Graham, D.L. 1997. Spider Webs and Windows as Potentially Important Sources of Hummingbird Mortality. Journal of Field Ornithology 68: 98-101.
4.Hanmer, D.B. & Dudley, C.O. 1988. Comments on Birds in Spider Webs. Nyala 12: 84-85.
5.Hayes FE 1995. Status, Distribution and Biogeography of the Birds of Paraguay. American Birding Association Monographs in Field Ornithology 1
6.Heck, B.A., & Heck, C.H. 2001. Common Yellowthroat Captured in Spider´s Web. Bulletin of the Oklahoma Ornithological Society 34: 19-20.
7.McKenzie, P.M. 1991. A Ruby-throated Hummingbird Archilochus colubris Trapped in a Spider´s Web. Journal of Louisiana Ornithology 1: 54-58.
8.Monroe BL, Sibley CG 1997 A World Checklist of Birds. Yale University Press.
FIG 1: Female Plovercrest Stephanoxis lalandi
(Photo Paul Smith)
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Photographs on this web-site were taken by Paul Smith, Hemme Batjes, Regis Nossent,
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