The main nest osprey chick is very settled and growing quickly. It will only be a matter of time before this chick will fledge from the nest and begin to explore the area around the Tweed Valley. This will be a very exciting time for all those interested in following the osprey’s story, as for the very first time, the main nest chick has been fitted with a satellite transmitter. This was carried out on the 9th July by Tony Lightley and Dave Anderson from Forestry Commission for Scotland under a special licence. During the process of fitting the transmitter, this 34 day old chick was also weighed and fitted with a darvic ring, (blue FX9) and BTO ring on the legs.
Telling the sexes apart
It was found that this chick weighed 1420g – meaning it’s a male chick. When determining the sex of the osprey chick, the bird is measured along the wing length and weighed. The smaller male weighs up to 1450g and the females can weigh in excess of 1600g. The female is the larger of the sexes but this is difficult to tell at a distance and in the field, and is only really noticeable when you have both side by side. Another pointer to tell them apart is by the colouring of the feathers around the neck. The male is very pale, but the female has a dark band of feathering for a necklace. The male also has a higher pitched call than the softer pitch of the female but again this is only obvious when both are together.
The satellite transmitter will enable us to follow the movements of this male chick and track his whereabouts for approximately the next four years of his life. Last year a ‘back up’ nest, female chick (FK8) was fitted with a transmitter and she is in Portugal. She is basing her summer months travelling between reservoirs and rivers in the region south of Sines.
New sites for the project area
Although there was some disappointment that a couple of osprey nest sites were unoccupied this year, it is encouraging to report that there are a couple of new sites within the Tweed Valley Project area. So overall, the population in this region is still promising to expand.
Feeding at the nest
Daily life at the main nest revolves around feeding, preening and resting it would seem. The male bird, white leg SS, brought in a fish to the nest on Monday which was still clearly gaping its jaws and gills. He looked as though he was about to tuck into a good meal for himself when his partner made a grab for it and removed it, somewhat ungraciously from his talons and began to feed herself and her bonnie young boy.
The osprey chicks fledge when they are between 40 and 50 days old and the period leading up to this first flight from the nest is spent building up the flight muscles in readiness. Regular wing stretching and flapping will occupy the chicks’ time and the frequency of this activity will increase as the chick nears the time to try out his wings for real. Sometimes a gust of wind can take a young bird by surprise and they can be uplifted on outstretched wings before they have actually made the decision to take flight. Watching the main nest live on camera has revealed some fairly comedic moments as the young birds in the past have tried to master their landing techniques when they return to the nest. However, life will be simpler for this chick – being an only offspring – as he won’t have to negotiate landing in amongst any siblings.
Thanks for reading,