The Manton Bay chicks are now 6 weeks old and they are starting to look more and more like their parents. At this stage the chicks are big enough for their blue Darvic and metal BTO rings to be fitted. The blue Darvic ring is fitted on the chicks’ right leg and the metal BTO ring is fitted on their left leg. These rings allow us and others to identify the individual, wherever the bird is, whether it is in Rutland, in their wintering grounds or elsewhere. By ringing the chicks, we will be able to gather some vital information on their survival and movements.
The three Manton Bay chicks were ringed early on Monday morning . A boat was launched from the fields behind and a ladder was lent up against the side of the nest. The three chicks were carefully lowered into the boat where they were ringed and other biometric data were taken. Maya and 33(11) were alarm calling above as the chicks were taken, this is now Maya’s 11th time experiencing this!
The ring numbers for this years’ brood are 1H1, 1H2 & 1H3. The biometric data taken indicates that all three chicks are females. When determining the chicks’ sex, the size of the bill, the thickness and length of the tarsus (the lower leg of birds) and their weight all play a part in distinguishing between male and female chicks. A typical weight range for males is between 1300 and 1500 g, whereas the weight for females is around 1800 g. The length of the tarsus also helps to tell between male and female chicks. Females have an average tarsus length of 57.9 mm though can exceed 60 mm whereas males have an average tarsus length of 53.6 mm, but can reach up to 58.0 mm.
Biometric Data for Manton Bay chicks 2022
|
Data Taken |
Manton Bay Chicks |
||
|
Darvic Ring Number |
1H1 |
1H2 |
1H3 |
|
BTO Metal Ring |
1380169 |
1380170 |
1380171 |
|
Sex |
Female |
Female |
Female |
|
Wing Length/mm |
366 |
358 |
332 |
|
Weight/g |
1830 |
1830 |
1770 |
|
Bill length (tip to cere)/mm |
29.6 |
29.4 |
30.9 |
|
Bill to head length/mm |
81.6 |
82.6 |
79.8 |
|
Bill depth/mm |
20.8 |
18.8 |
20.2 |
|
Tarsus thickness/mm |
14.8 |
14.3 |
14.4 |
|
Tarsus length/mm |
55.9 |
57.6 |
57.6 |
|
Tail length/mm |
132 |
138 |
128 |
Ringing is the only time these Ospreys will be handled and it is done as quickly as is safely possible and is always done by someone who has all the necessary certification and experience. As soon as the ringing was finished - and of course after we made sure the camera was spotless - the chicks were returned to the nest and we left the Manton Bay family to resume their normal way of life.
