Editing Common kingfisher (section)

===Feeding===
[[File:Common kingfishers (Alcedo atthis ispida) male passing fish to female.jpg|thumb|Male passing fish to female in spring courtship ritual]]
[[File:Alcedo atthis - Riserve naturali e aree contigue della fascia fluviale del Po.jpg|thumb|Male fishing in Italy's [[Po River]]]]
The common kingfisher hunts from a perch {{convert|1|–|2|m|ft|0|abbr=on}} above the water, on a branch, post or riverbank, bill pointing down as it searches for prey. It bobs its head when food is detected to gauge the distance and plunges steeply down to seize its prey usually no deeper than {{convert|25|cm|in|0|abbr=on}} below the surface. The wings are opened underwater and the open eyes are protected by the transparent [[Nictitating membrane|third eyelid]]. The bird rises beak-first from the surface and flies back to its perch. At the perch the fish is adjusted until it is held near its tail and beaten against the perch several times. Once dead, the fish is positioned lengthways and swallowed head-first. A few times each day, a small greyish pellet of fish bones and other indigestible remains is regurgitated.<ref name= Fry/>

The food is mainly fish up to {{convert|12.5|cm|in|frac=4|abbr=on}} long, but the average size is {{convert|2.3|cm|in|frac=8|abbr=on}}.<ref name="Fry" /> In Central Europe, 97% of the diet was found to be composed of fish ranging in size from 2 to 10&nbsp;cm with an average of 6.5&nbsp;cm (body mass range from <0.1 g to >10 g, average 3 g).<ref name="ReferenceA">{{cite journal |last1=Čech |first1=M. |last2=Čech |first2=P. |name-list-style=amp |title=Non-fish prey in the diet of an exclusive fish-eater: the common kingfisher ''Alcedo atthis''|journal=Bird Study|date=2015|volume=62|issue=4|pages=457–465|doi=10.1080/00063657.2015.1073679|s2cid=85632259|doi-access=free}}</ref><ref>{{cite journal |last1=Čech |first1=M. |last2=Čech |first2=P. |name-list-style=amp |title=The role of floods in the lives of fish-eating birds: predator loss or benefit?|journal=Hydrobiologia|date=2013|volume=717|pages=203–211|doi=10.1007/s10750-013-1625-3|s2cid=16257345}}</ref> [[Common minnow|Minnows]], [[stickleback]]s, small [[common roach|roach]] and [[trout]] are typical prey. About 60% of food items are fish, but this kingfisher also catches aquatic insects such as [[dragonfly]] [[larva]]e and [[water beetle]]s, and, in winter, crustaceans including freshwater shrimps.<ref name=Fry/> Amphibians such as the smooth newt (''Lissotriton vulgaris'') may also constitute part of the diet of this species.<ref>{{cite journal |last1=Davies |first1=Nigel |last2=Allain |first2=Steven J. R. |date=2023 |title=Smooth newts ''Lissotriton vulgaris'' as more than just occasional items in the diet of the Eurasian kingfisher ''Alcedo atthis''|journal= Herpetological Bulletin |volume= 164 |issue=164 |pages=43 |doi=10.33256/hb164.43 |url=https://www.thebhs.org/publications/the-herpetological-bulletin/issue-number-164-summer-2023/3809-13-smooth-newts-i-lissotriton-vulgaris-i-as-more-than-just-occasional-items-in-the-diet-of-the-eurasian-kingfisher-i-alcedo-atthis-i|doi-access=free}}</ref> In Central Europe, however, fish represented 99.9% of the diet (data from rivers, streams, and reservoirs from years 1999 to 2013).<ref name="ReferenceA"/> Common kingfishers have also been observed to catch [[lamprey]].<ref>{{cite journal|last1=Čech|first1=Martin|title=Lamprey (''Lampetra'' sp.) in the diet of common kingfisher (''Alcedo atthis'')|journal=Bulletin Lampetra|date=2017|volume=8|pages=44–47}}</ref> One study found that food provisioning rate increased with brood size, from 1498 g (505 fishes for four nestlings) to 2968 g (894 fishes for eight nestlings). During the fledging period each chick consumed on average 334 g of fish, which resulted in an estimated daily food intake of 37% of the chick's body mass (average over the entire nestling period). The average daily energy intake was 73.5 kJ per chick (i.e., 1837 kJ per 25 days of the fledging period).<ref>{{cite journal |last1=Čech |first1=M. |last2=Čech |first2=P. |name-list-style=amp |title=Effect of brood size on food provisioning rate in Common Kingfisher ''Alcedo atthis'' |journal=Ardea|date=2017|volume=105|issue=1|pages=5–17|doi=10.5253/arde.v105i1.a3|s2cid=90362897}}</ref>

A challenge for any diving bird is the change in [[refraction]] between air and water. The eyes of many birds have two [[Fovea centralis|fovea]]e (the fovea is the area of the [[retina]] with the greatest density of light receptors),<ref name= Sinclair/> and a kingfisher can switch from the main central fovea to the auxiliary fovea when it enters water; a retinal streak of high receptor density which connects the two foveae allows the image to swing temporally as the bird drops onto the prey.<ref name= Schwab/> The egg-shaped [[lens (anatomy)|lens]] of the eye points towards the auxiliary fovea, enabling the bird to maintain [[bird vision|visual acuity]] underwater.<ref name= Sinclair/> Because of the positions of the foveae, the kingfisher has [[monocular vision]] in air, and [[binocular vision]] in water. The underwater vision is not as a sharp as in air, but the ability to judge the distance of moving prey is more important than the sharpness of the image.<ref name= Schwab>{{cite journal| last= Schwab | first= I. R. |author2=Hart N. S. |date=May 2004 | title= Halcyon days | journal=[[British Journal of Ophthalmology]] | volume=88 | issue= 5 | page= 613 |pmid=15129670 | doi =10.1136/bjo.2004.045492 | pmc=1772125}}</ref>

Each [[cone cell]] of a bird's retina contains an oil droplet that may contain [[carotenoid]] pigments. These droplets enhance color vision and reduce glare. Aquatic kingfishers have high numbers of red pigments in their oil droplets; the reason red droplets predominate is not understood, but the droplets may help with the glare or the dispersion of light from particulate matter in the water.<ref name= Schwab/>