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Age Stages

Day 2 © E. Brendel

2 - 4 day old Common Swifts
Blind, from day 3-4 the first nestling down appears as black dots.
Between day 6 and 13 the eyes open.
From day 7 the quills of the main feathers pierce through the skin.
Care: Need a permanent heat source and must be fed and monitored every quarter to half hour with very small crickets.

Day 10 © E. Brendel

10 day old Common Swift
Eyes open.
Quills of the main feathers have pierced through the skin.
Care: Need a permanent heat source (28-30°C) and must be fed and monitored hourly with approx. 10-20 small crickets.

Day 15 © E. Brendel

15 day old Common Swift

Care: May still need heat source overnight.

Exception: severely starved or weakened animals need permanent heat.

They must be fed and monitored every 2 hours with medium-sized subadult crickets from approx. 7:00 am to 10:00 pm.

Day 17 © E. Brendel

17 day old Common Swift

Care: Heat source only needed for severely starved and weakened animals.

They must be fed and monitored every 2 hours with medium-sized subadult crickets from approx. 7:00 am to 10:00 pm.

Day 19 © E. Brendel

15 to 20 day old Common Swift

Care: Heat source only needed for severely starved and weakened animals.

They must be fed and monitored every 2 hours with medium-sized subadult crickets from approx. 7:00 am to 10:00 pm.

Day 20 © E. Brendel

20 day old Common Swift

Care: Heat source only needed for severely starved and weakened animals.

They must be fed and monitored every 2 to 2.5 hours with medium-sized subadult crickets from approx. 7:00 am to 10:00 pm.

Day 31 © E. Brendel

30 day old Common Swift

They must be fed and monitored every 2.5 hours with medium-sized subadult crickets from approx. 7:00 am to 10:00 pm.

© Dr. A. Pauliny

32 day old Common Swift

They must be fed and monitored every 2.5 hours with medium-sized subadult crickets from approx. 7:00 am to 10:00 pm.

Day 40 © E. Brendel

40 day old Common Swift

They must be fed and monitored every 2-3 hours with medium-sized subadult crickets from approx. 7:00 am to 10:00 pm.

Heavy juvenile swifts may now reduce their weight through increasing food refusal to achieve their optimal flight weight.

Day 43 © E. Brendel

42/43 day old Common Swift

They must be fed and monitored every 2-3 hours with medium-sized subadult crickets from approx. 7:00 am to 10:00 pm.

The fledging weight can vary between 37 g and 45 g depending on body size and wing length. The bird continues to be cared for until the plumage is fully developed, no single feather sheath is visible anymore, and it shows through its restless behavior that it wants to fledge. Before release, a final administration of Vitamin B Complex is necessary if the last one was more than 4 days ago.

© I. Polaschek

Feather sheaths on the underside of the wing
Decisive for release is a weight of approx. 38-40g and always the complete development of the plumage: Common Swifts are ready to fledge when no feather sheaths (small grey-white tubes from which the feathers grow, see image) are visible on the flight feathers of the underside of the wing.
Here: Feather sheaths visible - bird not yet ready to fledge!

Please follow the feeding table below, as the feeding amount (normally approx. 2-3 g medium-sized subadult crickets per meal per swift) can vary depending on age and size.

As with humans, there are large and small Common Swifts. Additionally, environmental influences can lead to developmental delays. Therefore, the relationship between age and body weight can vary without necessarily being a problem. For found birds, also check the appropriateness of the food amount ("Found Bird => Feeding => Feeding correctly").

The table below shows the weight development of the Common Swift "Jakob", who was hatched in the Swift Clinic in the 2012 season, hand-reared and successfully released. The values therefore do not represent representative averages. They serve as orientation and are meant to illustrate that weight gain can be quite irregular. For example, Jakob did not gain weight from day 15 to 17 and from day 19 to 22. In the final growth phase, when the swift is only growing feathers, it loses weight again. This effect, visible in Jakob from day 35, is normal and no cause for concern.

Day Weight in g Day Weight in g Remarks
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 Appetite decreases
14 34.6 36 43.8
15 36.4 37 44.4
16 36.5 38 43 Weight reduction
17 36.6 39 42.6 Takes little food
18 37.7 40 42.2
19 38.4 41 43 Looks at window
20 38.6 42 40.9 Still crawls back
21 38.2 43 39.2 Becomes restless
22 38.4 44 39 Flew !!!

Jakob was a delicate Common Swift. The values given here should therefore be interpreted as a lower limit.