Growth stages of the Common Swifts

This is dependent on diet and weather, as variations are possible.

1 day old Common Swift
At first featherless and blind

Handling: Need a permanent heat source, every half hour they need to be fed with very small crickets and they need constant attention.

2 - 4 day old Common Swifts

Still blind, at the 3rd or 4th day down feathers starting to show up as black dots.

Between the 6th and 13th day they start to open their eyes.

As of the 7th day the quills of the pennaceous feathers begin to pierce the skin.

Handling: Need a permanent heat source, every half hour they need to be fed with very small crickets and they need constant attention.

10 day old Common Swift

Eyes are open.

Quills of pennaceous feathers have pierced the skin.

Handling: Need a permanent heat source, every half hour they need to be fed with very small crickets and they need constant attention.

11 day old Common Swift

Handling: Need a permanent heat source, every half hour they need to be fed with very small crickets and they need constant attention

12 day old Common Swift

Need a permanent heat source, every half hour they need to be fed with very small crickets and they need constant attention.

15 day old Common Swift

Handling: Need a permanent heat source, between 7am and 10 pm they need to be feed every half hour with small crickets and they need constant attention.

17 day old Common Swift

Handling: Need a permanent heat source, between 7am and 10 pm they need to be feed every half hour with small crickets and they need constant attention.

Between 15 and 20 day old Common Swift

Handling: Need a permanent heat source, between 7 am and 10 pm they need to be feed every half hour to every hour and they need constant attention.

20 day old Common Swift

Handling: Need at least at night a heat source, between 7am and 10 pm they need to be fed every hour.

Between 20 and 30 day old Common Swift
Handling: Need at least at night a heat source, between 7 am and 10 pm they need to be fed every hour.

30 day old Common Swift

Handling: Heat source only if they are starved and weakened. Between 7 am and 10 pm they need to be fed every hour.

32 day old Common Swift

Handling: Heat source only if they are starved and weakened. Between 7 am and 10 pm they need to be fed every hour.

34 day old Common Swift

Handling: Heat source only if they are starved and weakened. Between 7 am and 10 pm they need to be fed every hour.

40 day old Common Swift

Handling: Heat source only if they are starved and weakened. Between 7 am and 10 pm they need to be fed every hour. The birds need to be fed until the feathers have completely emerged and they have reached a weight of at least 40g .

43 day old Common Swift

Handling: Heat source only if they are starved and weakened. Between 7 am and 10 pm they need to be fed every hour. If the feathers have completely emerged, ie; you can no longer see the calamuses, (see below) and the birds have reached a weight of at least 40g then they can be set free.

Calamus on the inferior side of the wing

To set the birds free it's essential that they weigh at least 38 - 40g and the feathers have to be completely emerged. Common Swifts are fledgelings, when the calamus (small gray/white tubes, where the feathers grow out) on the primaries of the inferior part of the wing is not viewable anymore.

Photo: Calamus still viewable - bird is not yet fledged!

Weight stages of Swift nestlings

Much like humans, some swifts are taller or smaller than others. Environmental conditions may inhibit the nestling's development, too. Hence, the nestling's weight-to-age relationship is not fixed, but may vary by a few grams. In case of a found bird, you should also check the amount of fodder. ("Found birds => Feeding => How to do it right").

The table below displays observations taken from "Jakob", a swift that was bred in the swift clinic, raised by hand, and successfully released in 2012. As such, they should not be interpreted as representative mean values. They rather serve illustrative purposes and as an orientation point. Note for instance, that Jakob did not gain weight between the 15th and 17th day as well as between the 19th and 22nd day. In the final stages, when the nestling's body is grown, but the feathers still show calamuses, a there is a typical loss of weight. In Jakob's case, this is from the 35th day onwards.

Tag	Gewicht in g	Tag	Gewicht in g	Bemerkung
1	2.4	23	40.6
2	3.3	24	40.7
3	4.4	25	41.7
4	6.7	26	43.8
5	8.1	27	42.2
6	10.6	28	43.7
7	13.7	29	43
8	17	30	46
9	20.7	31	43.2
10	22.9	32	45.7
11	26	33	45.2
12	29.4	34	46.3
13	31.8	35	44	Freßlust läßt nach
14	34.6	36	43.8
15	36.4	37	44.4
16	36.5	38	43	Gewichtsreduktion
17	36.6	39	42.6	nimmt wenig Futter
18	37.7	40	42.2
19	38.4	41	43	blickt zum Fenster
20	38.6	42	40.9	krabbelt noch zurück
21	38.2	43	39.2	wird unruhig
22	38.4	44	39	geflogen !!!

Jakob war ein zierlicher Mauersegler. Die hier angegebenen Werte sollten also eher als Untergrenze interpretiert werden.

Growth stages of the Common Swifts

Weight stages of Swift nestlings

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