Head-bobbing in the Ring-billed Gull (Larus delawarensis)

Thomas J Lisney, Nikolaus F Troje


Many birds bob their head as they walk or run on the ground. The functional significance of this behaviour is unclear, but there is strong evidence that it plays a significant role in enhancing visual perception. If head-bobbing is advantageous, however, then it is a puzzle that some birds do not head-bob. As a group, gulls (Laridae) are among the birds that reportedly do not head-bob,yet here we report head-bobbing among Ring-billed Gulls (Larus delawarensis), observed and filmed in Ontario, when walking relatively slowly while foraging on the ground. This suggests that head-bobbing plays a key role in the visual detection of food items in this species. We suggest that head-bobbing may be a relatively common behaviour in foraging Ring-billed Gulls and speculate that other gulls (and indeed other birds) previously thought not to head-bob may in fact do so under certain circumstances.


Ring-billed Gull; Larus delawarensis; head-bobbing; behaviour; foraging; head movement; head stabilization; motion parallax; visual perception

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DOI: http://dx.doi.org/10.22621/cfn.v130i2.1843

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