Posted this afternoon on Dyfi FB
Paul WildlifewriterDyfi Osprey Project
“The Yolk's On You”
(An overfeeding thought for the day)
... How much food does an osprey chick need in the first few hours after it hatches? Nobody has asked this question, because we all instinctively know the answer – it must need food immediately, and preferably lots of it. It's a baby animal and they're all the same in this respect, right?
Not exactly.
In its last few days before hatching, the still-developing chick does a remarkable thing. It has been obtaining all necessary nutrients from part of the egg yolk – a store that (obviously) gets smaller as it gets larger. Just before emerging from the egg, the chick resorbs the remaining yolk through the umbilicus and into its abdomen. We can see that chick #1 in the photo above has a slightly distended tummy, indicating that this has happened properly.
Filled with protein and other vital nutrients, the resorbed yolk provides enough food for its first full day in the outside world. During that same day, enormous changes are happening within its little body... Its digestive system switches over from low-level activity to a much more complicated state that will enable it to break down and convert fish. The endocrine and hormonal systems ramp up by a factor of several hundred times: it's thyroid gland becomes fully operational for the first time, and structural changes start to occur in the liver and kidneys.
But although the chick does not need a large quantity of food in its first day, the parent birds will begin bringing fish to the nest and offering small pieces of it. Some of this, the chick will eat – even though it can't quite digest it properly as yet. What it REALLY needs from this first sample of fish flesh is the water contained therein. This is absorbed rapidly because, in the first few days of life, a chick is at much greater hazard from dehydration than it is from starvation
Cas Posts: 195Joined: 27 May 2013 19:17
No need to worry ? Well,we worry anyway.
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