Foulshaw Moss intruders...

Blue V2 Osprey chick 2015 on nest. Cumbria Wildlife Trust

Intruders from the air that is! Three (probably four) other adult ospreys seen around the #FoulshawOspreys nest.

Hi, Simon here. Its about time you had an update on all the goings on with the #FoulshawOspreys. Below are the latest highlights from the nest web cam plus my notes on what you are seeing.

OK, so 'intruders' may sound a bit harsh, but our resident ospreys were clearly very cross at the appearance of additional adult ospreys in recent weeks. Many visitors have been treated to views of the visitors sitting in the trees or circling overhead and performing display flights, slowly descending in a zigzag glide.

On a serious note we do sometimes also have people trying to get near to the nest, apparently to take photographs. Recklessly disturbing nesting ospreys is of course an offence, with maximum penalty of six months imprisonment plus £5,000 fine.

Nobody should be going beyond the Foulshaw viewing platform without a permit, but unfortunately the actions of a few thoughtless individuals mean we need the nest cameras for security as well as observing the birds.

We rely on donations, as entry to Foulshaw Moss is free. If you enjoy watching the ospreys and can spare a little bit to help keep streaming the webcam or improve visitor facilities, we would be really grateful.


At least 5 ospreys at Foulshaw Moss

Thanks also to everybody who has let us know when they have watched the webcam and seen displays of defensive behaviour suggesting that another osprey is around. That is always really useful, as is information on the exact times when anything interesting was noticed.

The video highlights start with some examples of ‘mantling’, a common defensive behaviour in birds of prey, which ospreys usually do when another osprey intrudes on their territory. This is essentially spreading the wings and tail, and hunching the shoulders. Most species do it to shield a prey item that they are eating. On a number of occasions this year, Blue 35 has kept this up for over an hour.

Nesting ospreys like to embellish their mantling display with some bobbing up and down, some shifting from foot to foot, and lots of shrieking. Another posture to look out for is the alarm display, where they sit very upright, with the wings pulled in tight at their sides.

When alarmed, the young will flatten themselves down and remain still, which makes them camouflaged against the nesting materials. At one point, Blue 35 can be seen doing a similar thing when a bird is circling above her. She lies her body and head flat down, with her bent wings out flat besides her (see 3.30 in the video).

At one point 4 distant birds can be seen circling together. Although they can’t be positively identified as ospreys from this film, this strongly suggests that there were 2 non-breeding pairs in the area, since our male, White YW, flew back to the nest with a fish shortly afterwards. He would not have left if he had been there during this intrusion.

And intrusion it certainly was! A female dropped down onto the nest (see 2:47 in the video & photo above). Clearly no match for the look of rage on Blue 35’s face, she took off again seconds later. The chicks were laying in between the 2 adult females, so no fighting ensued. She has no leg ring so I can’t positively ID her. Does anybody recognise this bird from any other osprey nests?

Apparently, physical fighting is rare amongst adult ospreys, and no physical contact has been witnessed when they have flown up and given chase to the various osprey intruders. The chicks, though, did plenty of it. Now a pecking order is well established, harmony has been restored.

Where are they hiding?
This video also tries to answer some of your questions about what the adults are up to when not visible on the nest camera.

At 3:38 we see the roost tree, a nearby dead tree where both adults like to rest or sit and eat in peace. Notice the red deer grazing beneath on this summer evening. They can sometimes be seen in the long grass in the daytime too. If not there the male may be out fishing in the River Kent or further along Morecambe Bay, though he is still finding time to spend most of the day snoozing.

Both birds also keep going on the hunt for new nest material. The strange blackish object at 4:44 apparently turns out to be tree bark. This is frequently used to line osprey nests, as well as grass and moss. As to why they keep depositing new nest material on top of the sleeping chicks, I’m afraid I really have no idea.

At 4:54 the camera catches White YW resting on a branch below the nest, well out of the usual field of view. Both birds often do this. At the moment Blue 35 tends to roost on a branch next to the nest, just out of camera shot, thereby giving the impression that she’s not there.

As the 3 chicks are growing, White YW is of course having to spend more and more time out hunting fish to feed them. We are still very keen to hear where they are going to, so if you spot an osprey outside of the Foulshaw Moss nature reserve, please add a comment below or ring/email us with the date, approx time and location.

The chicks faces give away where Blue 35 is hiding at 6:08. She has taken to perching on top of the cameras, much to our amusement. When you visit the osprey viewpoint, have a look for yourself!