Osprey Diary at Loch of the Lowes – Week 12
It’s been another fine week weather wise in Highland Perthshire, with sunny weather dominating over the weekend, followed by cooler, more overcast (but still very dry) conditions in the latter half of the week.
The chicks have been making use of their mother NC0 like a parasol, using her shadow to take shelter from the direct sunlight.
The chicks continue to grow at a rapid rate, with their lives comprising of a daily routine of preen, eat, sleep, stretch, repeat! We all like a lazy Sunday morning and it appears that so do our young ospreys! After a good breakfast, the youngsters spent the morning sleeping off their meal, napping and partaking in a spot of yoga, with some healthy wing stretching and ‘downward dog’!
The male osprey LM12 appears to be fully recovered from his injury and is flying well, with his time largely taken up hunting, defending the territory and chasing off intruders.
Intruding osprey are still proving to be causing disruption to life on the nest, either requiring direct intervention, or an active presence on the territory to discourage any attacks – this of course has a knock on effect onto LM12’s capacity to leave the area to go and hunt. In the last week there have been some persistent intruding incidents from an unringed female osprey, a sky-dancing male looking to impress NC0 with his fancy flying moves, and a ringed Scottish osprey – unfortunately we were unable to get a clear view on the ring to ID.
In the clips below, NC0 warns off the first intruder with a series of high pitched ‘chipping’ guard calls, whilst mantling with her wings to make herself look big and protect her young. For the second incident LM12 provides reinforcement on the nest. This time the pair go up a level in their vocal defense, emitting a series of repeated alarm calls, warning the intruder off the nest. Often the chipping guard and alarm calls are enough to ward off any unwanted attention, avoiding any more risky aerial defensive maneuvers.
When it has been calmer LM12 has been able to focus on hunting and leave the territory to seek out the best fishing grounds. He certainly hit a purple patch at the weekend, bringing in a record 7 fish in one day!
Since his record breaking day, the quantity and size of fish coming into the nest has fluctuated. There are number of possible explanations for this. In addition to intruder pressure on the territory, there will inevitably be an increase in the number of osprey hunting in the wider area, creating added competition at the top fishing spots. This combined with unprecedented dry weather conditions, could be affecting both the amount of available insects and in turn the number of fish coming to the surface to feed.
The very cold and dry spring in the earlier part of the season, with constant easterly winds, seem to keep fish deeper in the water due to less insects hatching. More recently the river levels have dropped significantly due to the warm and sustained, extremely dry conditions. This again might be forcing fish deeper to avoid the shallow, warmer water, and forcing LM12 to go on hunting trips further afield than usual.
It is also unknown whether the extremely hot weather of last season has impacted the spawning and survival of newly hatched fry. There certainly has been an observed lack of perch coming into the nest this season, which naturally go though cycles of oscillating numbers. This in turn could be affecting pike numbers who will predate on perch in the nearby lochs.
All of this points to a complex ecosystem that ebbs and flows each season in relation to changing environmental conditions, illustrating the interconnected nature of species from insects right up to ospreys as apex predators. It will be interesting to see how any future weather patterns throughout the season impact the quantity and variety of fish being brought to the nest.
Meanwhile, the fluctuations in fish deliveries has sparked some fiesty, sibling rivalry on the nest. This of course is normal behaviour, with the younger chick quickly adopting a submissive position until its sibling has had its fill. Sometimes this requires several larger fish to come in to satiate the larger, more dominant chick, but when it does contentedly settle down into a food coma, ‘Bob 2’, is being well fed by NC0 until it too has a bulging crop. Patience certainly seems to be a winning strategy.
With the chicks growing rapidly, and becoming more mobile on the nest, NC0 is spending more time perching and preening on top of the camera and on her favorite ‘split birch’ lookout.
It won’t be long before she starts to roost on the bough that extends out from the nest to give the youngsters more room. For now at least, the chicks aren’t so big that they don’t still enjoy a good ‘courie’ under Mum!
Talons crossed for more days like ‘Super-Fish Saturday’ to keep things relaxed and content on the nest.
Make sure you stay tuned to the live webcam to follow the action and keep up to date with the daily lives of the ospreys by following us on Twitter or Facebook for regular updates.
‘Raz’ Rasmussen, Perthshire Ranger
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Preface
It’s been another fine week weather wise in Highland Perthshire, with sunny weather dominating over the weekend, followed by cooler, more overcast (but still very dry) conditions in the latter …