Reproduction
Since Charadriiformes is such a diverse order, one can expect their reproduction strategies to be diverse as well. Most members are monogamous in choosing their mates, and some keep the same mate year after year. In these monogamous relationships both the male and the female take turns taking care of chicks and defending the nest. Others are polygamous where a male mates with several females, and the remaining group known as polyandrous are when a female mates with several males.
Some members such as terns, gulls, and alcids are known for colonial nesting. In this type of nesting large numbers nest and raise their young in a single location; as many as a hundreds of birds can gather in a single location. These birds generally nest in habitats near the shore where resources are abundant and can sustain high numbers of individuals.
Charadriiformes are not known for their intricate nest making skills. Most of the time their nests consist of just a hollowed out spot in the ground lined with a few twigs or pebbles. A few do build nests in trees, some use abandoned nests, and some don't build any nests at all. Females generally lay anywhere from one to four eggs, and incubation lasts at least three weeks. When it comes to being precocial or altricial, it depends on what type of bird it is. Shorebirds tend to be precocial with a some down and are able to move fairly well. Seabirds on the other hand are altricial and are born blind and bald requiring more care.
Common Murre
The common murre is a species that demonstrates a monogamous relationship. They spend most of their offshore at sea, but when breeding season comes around the male begins to show courtship displays, and once a mate is found they come ashore to mate and lay eggs. Since both sexes are similar in plumage the male makes itself stand out to the female by bowing and preening. When a male is directly in front of a female it will throw its head back with its bill pointed up. When a female has chosen a male mutual preening between the two can be observed.
Common murres are colonial nesters and are unique in their site fidelity. They are known for having the smallest nesting territory known to birds because of an extreme amount of birds coming to nest on sea-cliff ledges. Quarters get so tight that males often poke at others with their sharp bills in order to defend their territory. Even though these birds are monogamous, since there are large numbers of birds in a small area, extra pair copulation does occur when females are unattended.
Breeding season takes place during the middle of May and early June. Once the female is ready to lay its single egg it will do so on a bare rock; common murres do not build nests. The egg itself is pear shaped to keep it from rolling off the the cliff and generally matches the color of the rock to keep it camouflaged. If the egg is lost however due to rolling off or predation, the female will lay another one two weeks later. Incubation lasts about thirty-two days, and since the pair is monogamous, they will take turns about every twelve hours.
Common murres are precocial and chicks are born with a coat of down. Both parents help to feed the chick for three weeks until it fledges. At this time the chick will go out to sea with its father until it can properly feed and fly by itself. These birds have a slow life history (k-selected) and the chick will not reach reproductive maturity until about four or five years old. They can live up to about twenty years old giving itself enough time to reproduce and increase its fitness.
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| Breeding Grounds |
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| Common Murre Chick |
Killdeer
Killdeer is another species that participates in a monogamous relationship. Males usually arrive first on the breeding grounds in the spring and begin to claim their territory. They usually claim their grounds on either fields or shores, and once they have gained their territory they start their courtship displays to let the females know that they are available. They usually hover over their territory while beating their wings in a slow motion and making a loud call. Both male and females also expose their orange rumps and fan their tail feathers. When the male has found a female they work together to make the nest by making a scrape in the ground. They often make several scrapes in the ground so that when predators comes they may not pick the right scrape with the eggs inside. They may place small rocks or twigs inside the scrape.
On average the female has a clutch size of four eggs and can lay one to three broods in a season. The eggs are usually a neutral color with some black spots that blend in with the scrape. The eggs are very difficult to see even when the exact location of the nest is known. If eggs are lost one to three replacements can be added. Both parents incubate the eggs for about twenty-eight days until they hatch. Killdeer chicks are precocial and when they hatch they are covered in a coat of down. As soon as their coats dry these chick are ready to go and take care of themselves; the parents play no role in feeding the chick other than leading it to a feeding area and only serve as protection until the chick is ready to fly. At about a month later they fledge and are completely on their own after that.
Killdeer can live up to ten years giving it a slower life history. Chicks are ready to reproduce by the following spring which gives them plenty of time to replace themselves and increase their fitness.
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| Killdeer Nest |
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Killdeer Chick
References
"Common Murre." Common Murre. N.p., n.d. Web. 26 June 2012. <http://www.oiseaux-birds.com/card-common-murre.html>.
"Killdeer." Killdeer. N.p., n.d. Web. 26 June 2012. <http://www.oiseaux-birds.com/card-killdeer.html>.
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