RECAP

It’s been nearly ten weeks since long term breeding female ‘Blue NC0’ returned from migration and 7.5 weeks since she was last sighted at Loch of the Lowes.

 

The early season has been unusual to say the least, with no less than a combination of four pairings attempting to settle on the nest. A recap of what happened in those early weeks (including an explainer video) can be found here

Finally on the 13th April, the pairing of LM24 (the male known as the ‘Dark Intruder’ who established himself on territory last season, after the untimely death of the resident male LM12) and LF25 (the dark female briefly referred to as ‘Bandit’) established themselves on the territory to become the resident breeding pair. Interestingly, LF25 was one of the repeated intruders last season who attempted to assert herself on the nest!

 

NAMING

As per all unringed birds, the pair are named according to the system used at Lowes which helps track how long a bird has been holding territory/breeding on the reserve, with LM24 being Lowes Male 2024, and LF25 being Lowes Female 2025.

 

IDENTIFICATION

Despite their lack of colour rings to help with identification, the pair have several unique features that make them relatively easy to identify from other osprey landing on the nest.

Most strikingly is LM24’s cat’s-eye looking pupil, caused by a rare genetic “inherited defect affecting the membranes of the eye, leading to irregularities in the shape of the iris and pupil.”

In some instances the malformation could be “caused by external environmental stressors, including toxin exposition, vitamin deficiency and parasitic and viral infection”, or that an impact injury to the eye could create something that looks similar, but it would require a closer medical examination to know for sure. Regardless of the cause it certainly does not seem to be impacting his fishing! [Mikula et.al 2025)

 

Further features which are unique to LM24 include a darker chest than what is typically observed on other males, and many markings on his head, including the impression of an oak tree with a leafy canopy, trunk and root system on the rear.

 

Lastly, he also has numerous beautiful large dark ‘thumbprints’ on his underwing.

 

Like her partner, LF25 is also a dark bird but with a much thicker ‘eye mask’ that fully covers her eyes, which steps down at right angles before running into her neck.

 

The pattern on the rear of her head is noticeably different to LM24, appearing more like a triangle of brown with a snaking line extending from the top of the triangle towards her forehead. This can also give the appearance of a large white heart when she bows her head down into the nest cup.

 

Her beautiful dark chest, is matched by the striking dark marking on her forehead, almost like a feathery, heraldic ‘fleur-de-lys’ but with a unique white patch between her eyes and the impression of heavy ’emo’ eyeliner.

 

As with all ospreys, the females are larger than the males, providing an extra large ‘Mumbrella’ to safely incubate the eggs and then later brood and protect the rapidly growing chicks from both the sun and the rain.

 

FISH

After finally cracking how to mate the right way round, LM24 set about proving to LF25 that he would be a good provider for the family. Helped by plenty of vocal encouragement he upped his game, delivering fish frequently to the nest, ranging from small ‘snacklets’ of pike and perch caught in front of the hides, to larger grayling and rainbow & brown trout from the lochans and rivers nearby.

EGGS

It has been clear throughout the season from LM24’s early back-to-front mating attempts, and the pair’s somewhat ramshackle nest building, lacking in its usual deeply, lined nest cup, that both LM24 and LF25 are first time breeders.

It took some time for LF25 to feel settled and confident enough in LM24’s abilities that he could both defend the territory and provide enough food for any future chicks. On the 4th May, 22 days after their first mating, LF25 finally got down to the business of laying, but not before a stressful extended period of having to deal with an intruding female on the nest, who not only tried to usurp her, but stole and ate her fish in the melee of wings and talons.

After 2 long hours, and some awkward posturing, with LM24 stuck in the middle of the two females, the rogue osprey was finally seen off! It’s no wonder LF25 had seemed unusually reticent to chase off the intruder, as no sooner had she gone, she readied herself to lay!

LM24, unaware of what was about to happen, or what her vocalisations meant, ‘helpfully’ attempted to mate with her mid-lay! Having shrugged off his advances, at 13:58 and after 10 minutes of squeaking, grunting and wandering about, the first dark reddish-brown egg made an appearance. Appearing a little unsure of what to do next, LF25 partially hovered over the egg for a time, before finally settling down to incubate.

Whilst it took a day or so for her to really get comfortable with hunkering down on the egg, LM24 quickly proved himself to be an attentive father, and was quick to give his mate plentiful breaks, appearing like clockwork at first light and throughout the day to give LF25 some time to stretch her wings, wash, preen and eat.

A few days later, on the the 7th May at 10:23am, the second egg appeared, also a deep, reddish brown in colour, but with some more noticeable, paler white sections.

Typically ospreys will lay an average clutch of 3 eggs, however it is not unusual, as in LF25’s case, to lay only two. In many ways this takes a bit of pressure off the young pairing, as should the chicks manage to hatch out, there will be less competition for food

 

SETTLING INTO A ROUTINE

Over the coming days and weeks, the pair have settled into a comfortable routine.  It has been fascinating to observe the increased understanding between the pair develop, from contact calls when arriving and leaving the nest, to making sure the nest is always protected, as if they were on a piece of invisible string.

Apart when out fishing, LM24 has nearly always been ‘on-wing’ nearby to support his mate, often popping up like a harrier jump jet to take over incubation duties or provide defence against intruders, including a ringed osprey PH9, who landed on the nest on 24th May. It is thought that PH9 is young male osprey from another Perthshire nest.  More details to follow once confirmation of his history has been received from the Roy Dennis Foundation.

 

UNFORTUNATE ACCIDENT

Unfortunately, during a fish delivery at 7:15am on 20th May, LF25 accidently stood on what looked to be Egg 2. Although it didn’t look like there was damage at the time, by 10am a hole could be seen in the egg. It wasn’t until much later in the morning that LF25 moved the egg out of the nest cup, with LM24 finally removing the empty shell to the edge of the nest at 13:29.

With it being the first breeding year for this young pair, accidents and mistakes are inevitable. Due to their inexperience, the nest appears to be quite shallow, without a deeply lined nest cup to keep the eggs safely tucked up. As a result, the eggs have been sitting proud on the bottom of the nest, making it more challenging for the pair to keep them centred when turning them over, and a little more prone to being knocked about and stood on, particularly if they forget to curl up their talons when walking about, known as ‘knuckling’.

It is worth remembering that the previous resident female NC0 only managed to fledge one chick in her first season, despite initially having two fairly well developed youngsters – mistakes are all part of the learning process, not to mention a dose of good luck. On the more positive side, it does mean should a chick hatch, the odds on its survival have gone up markedly, with no other competition for food. Fingers and talons crossed for no further mishaps.

 

CHALLENGING WEATHER

Despite the extremely dry conditions and worryingly low water levels in the surrounding lochans and rivers, LM24 has been providing a steady supply of small to modest sized fish. At this stage in the season, there is no need to be delivering a huge amount, and whilst his number has dropped in the past week, he did surpass himself earlier in the month with a record 6 deliveries!

 

You have to be tough as an osprey! With their nest typically perched at the very crown of a broken topped tree, the 360 degree view which they love and enables them to see intruding threats from far and wide, does expose them to all of the elements; sun, wind, rain and….well let’s hope we don’t get the ‘s-word’ in May, but as they say “Ne’er cast a cloot till May be oot!”

Thankfully, at long last the reserve and surrounding area has been receiving a good dose of rain. Despite the heavy overnight downpours, LF25 hunkered down, the instinct to incubate and keep her precious remaining egg dry and warm, overriding any desire to seek shelter.

It will be interesting to see if the recent rain causes any changes to LM24’s fishing routine. At the time of writing he has been spending a lot of time dropping in on unsuspecting perch and pike in front of the nest, wowing visitors with his flying skills!

 

WHEN WILL THE EGG HATCH?
All being well in just over two weeks time the remaining egg should hatch. On average incubation lasts 37 days, so assuming it was Egg 2 that was destroyed, we should hopefully see the appearance of a little osprey chick some time around the 10th of June, give or take a few days! That said, a lot could happen between now and then.

Don’t forget to follow the webcam to keep up to date with all the latest action from the nest, or even better, come and visit the centre for fantastic loch side views.