Saturday, May 24, 2008
Derby Cathedral Peregrine Project: 3 weeks old
The 4 eyases decided they like the other side of the nestbox better. So they moved to stay.
But they did not know we can hardly see them overthere, but fortunately the project member changed the cam. Dear eyases now you can see how much we care for you all. Whatever you decide to do, the 4 of you, we will definitely follow....
The eldest eyases are stepping into their 4th week of development. Their weight is now more than 500 gram each. They are covered in white down, but we can see the retrices and remiges coming through very clearly now. The feathers are still protected by the shaft in which they grow. As we have seen, the chicks are able to walk now instead of moving around on their tarsi. Chicks always start to explore the immediate area around the scrape around this time. The parents stay around to watch the whole thing and to take care nothing happens. The chicks excersise their wings frequently to built up muscle power. They have to, the flight muscles need al lot of training to get strong enough to fly in 3 weeks. They are very communicative as well. They "talk" al lot to eachother and to the parents and have quite a rich language in sounds.
http://derbyperegrines.blogspot.com/
De Mortel 34 days old
The De Mortel eyases are growing very fast into beautiful juveniles. De 2 eldest ones, a male and a female are 34 days old today. The male is, because he is smaller much sooner ready to step outside and will fledge sooner than his sister.
The male was indeed the one who stepped outside today on the gris in front of the nestbox and stayed there for a while. I'm sure his sister will follow soon. The 2 youngest ones, will probably wait a while.
Zurich: just parents
No sign of both juveniles today, just the female came by. She is one beautiful peregrine falcon.
Nijmegen: 33 days old
It's such a shame the nestcam is so dirty. But fortunately the eyases are growing quickly to the moment of stepping out on the grid. So we can watch them closely again.
They are stepping closer and closer to the doorway very nosy as they are.
Their appearence is changin very rapidly now. They are in their white pantaloondays. This may happen a day or two earlier or later, but most chicks do go through this phase where they have large fluffs of down conspicuously surrounding their legs, much more prominently than anywhere else on their bodies.
New Yersey: looking great!
After all the troubles and the death of 2 eyases things are looking very good now. The one eyas who was very sick, near death and was taken into hospital is alive and kicking again. Both have been banded this week and are very healty. The rampage is moved in front of the nestbox so when the eyases want to explore the world outside the nestbox, they will be able to come back.
Terminal Tower Cleveland: 32 days old
It's a shame the camposition is from so very far away, that we can hardly see an eyas anymore. I know they are on the move, but a little closer would be great.
Eyas to Juvenile development
Click the pictures to enlargeCondition At Hatching
The peregrine falcon eyases are semialtricial, nidicolous; covered with off-white (prepenne) down. Semi altricial means: Covered with down, incapable of departing from the nest, and fed by the parents. In species like the peregrine falcon we speak of semi-altricial 2, hatch with the eyes closed.
The bill and feet pinkish to pale gray with eyes closed. They weigh about 35–40 g. If eyes open with food-begging first day, they are slitlike. The eyases obtain 2 downy plumages.
Growth and development
At 5 days after hatch, their mass has doubled. The eyas can sit with relative ease, and the open eyes are more round.
At 6–8 days of age the second down (mesoptile or preplumulae) starts to emerge, first on humeral and alar tracts but no down visible on belly at 6 day, although on the legs and belly at 8 days.
Also second down is well out on the wings and looks a bit blueish and sheaths of primaries breaking skin on wings.
By 10 days of age the second down is complete and uniform and outer rectrices are breaking skin. At 10 days, primaries growing at 2–3 mm/d, rectrix sheath not yet split.
At 14 days the second down is dense and long, rectrix sheath about 2 mm and typically ninth primary emerges from sheath.
By day 17 the contour feathers start to push out prepennae and only pale (buffy) tips of rectrices have emerged but growing at about 2 mm/d (since day 13).
By 10 days of age the second down is complete and uniform and outer rectrices are breaking skin. At 10 days, primaries growing at 2–3 mm/d, rectrix sheath not yet split.
At 14 days the second down is dense and long, rectrix sheath about 2 mm and typically ninth primary emerges from sheath.
By day 17 the contour feathers start to push out prepennae and only pale (buffy) tips of rectrices have emerged but growing at about 2 mm/d (since day 13).
At 20 days while still with heavy coat of second down, brown contour feathers are visible on margins of wings, tail, and faintly around the eyes.
By 30 days young appears about half down-covered and half feathered; while side of face well feathered, crown still covered with down.
At 35 days while mostly feathered, large conspicuous patches of down around legs, under wings, and on crown.
At 40 days almost fully feathered with traces of down on crown and under wings and outer several remiges; rectrices not fully grown but bird capable of weak flight.
From my Peregrine falcon website:
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