Only a few weeks ago, Midway Atoll NWR was filled with a carpet of black-and-white Laysan Albatross quietly and patiently incubating. Now, the checkerboard scene of adult albatross has been replaced with downy nestlings and a constant murmur of peeps. Upon hatching, tiny Laysan and Black-footed Albatross nestlings are brooded by their parents for the first few days. Sometimes, as you walk by, you might catch a glimpse of an albatross chick's head peeking out from under its parent's wing or tail. But, the albatross chicks grow quickly. For example, with Black-footed Albatross nestlings, the middle toe, culmen, and tarsus tend to grow at a steady, linear pace for the chick's first 75 days; the wings, though, grow exponentially. In fact, Black-footed Albatross nestling mass can increase as much as 0.6 kilograms after one feeding. With such quick growth, albatross nestlings become too large to be brooded, and parents will begin to nest guard instead (although they will try to brood for as long as possible... many times you will see a parent albatross trying to brood a chick almost as large as the parent itself!).
At this point, most of the Laysan and Black-footed Albatross nestlings are at the stage that they are no longer being brooded. One (or sometimes both) of the parents may be spotted guarding their nest and precious nestling, but many of the nestlings are seen completely alone. Fields once filled with mature albatross, some incubating, some dancing, are now starting to empty out, with only neat nest cups and downy, pear-shaped, masses of chicks left behind. Once quiet and contained, the nestlings are now busybodies, constantly re-arranging and maintaining the nest cup site. With the parents absent, though, the nestlings begin to explore the wide world around them, sometimes wandering as much as 30 meters away from the nest. As with all albatross, from tiny nestlings to majestic, mature adults, there is wanderlust in them all. But, unlike their sleek and (usually) graceful parents, the nestlings are quite plump and unwieldy; as they waddle around, you can spot their tiny footprints with a well marked "belly print" in between. After their exploratory excursions, they almost always return to their nest site to be fed. In fact, parents will not feed their nestling until it returns to within a few meters of the nest. According to Birds of North America, older nestlings will respond to vocalizations of parents by approaching and soliciting food, often making a begging "peep-peep" call. In comparison to the steady presence of parents during the brooding stage, parents visit their chick only briefly during the post-guard stage. A single visit may last only 15-25 minutes during which the nestling is fed 3-4 times. After that, the parent takes off again, heading out for another expedition to find food in the cooler, more productive waters up north while their chicks wait behind.
1 Comment
Leslie Carpenter
1/3/2015 11:15:45 am
wondering what the predation rates are like?
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About MeWieteke Holthuijzen: budding environmental scientist, passionate birder. Archives
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