Osprey Q & A

Thanks Keith, I look forward to that.

CRINGER and ALL INTERESTED PARTIES

Until a few years ago I thought in general that ospreys only learned to fish after they had left the nest and had started their migration and that disposition dictated that. I still think that is the case in general but I did observe some very interesting habits from two different nests in 2010. Unfortunately one of these nests failed last season as I wanted to repeat this study.

First may I discuss the nest at Lochter outside my home town (Iam not giving nest information away as this is a public viewing nest with cafe and Camera and TV monitors).

This particular nest is man made on a 60ft Douglas Fir directly overlooking the Fishery Pools and during the chicks development they can watch everything their parents do from the nest.

After fledging the chicks would still sit on the side of the nest or a nearby tree and certainly by evening would be screaming at their father for him to bring them food. This was repeated evening after evening except he declined to bring in fish but instead lured them over the fish lake themselves. As they all hovered over the lake he would go into a dive but never came out with a fish which was strange because he only ever took one dive and always caught the food on tap. The chicks appeared to get the message not at first but within days and started copying him and at first they were not successful but as time went on were very proficient for what I thought they had to learn the hard way on route.

Now I believe this only occured because of the location - Had this been away from the fish lakes then the birds in their younger days hang around the nest  and the male would not have neen able to demonstrate this - Why this conclusion Nest 2.

This is approximately six miles away towards Bennachie may be a little more but the food source is the same fishery similar to a Rothiemurchus set up (A Tesco supermarket for Ospreys). Again well know so no give aways here and only a general direction.

After fledging the male would do his usual trips to the fishery as he had done all season - How do I know - I often watched him at the nest bringing in fish and often also at the fishery catching coming in from the direction of the nest and flying off the same direction. TIGER will know I am not a good ID of particular Ospreys (I get 0/10 on his quiz but I got 1/1 yesterday evening - My Favourite friend at present - careful CRinger he is my star who may bring down your client - LOL) so have to take photographs and do comaprators but he was the same male.

Now here the juveniles after fledging did not follow mainly because initially they do not wander far from the nest.

As time went on I used to go to this nest and no one was around - no particular worry that is the young growing up and spending time away exploring or even resting close by.

At the fishery I did see another juvenile apart from the residents come in from afar in the direction of the nest 2 so assumed this may be one of these juveniles but only singly and not accompanied by a parent or as a group. He/She used to come in regularly late season and eventually was successful in a catch at the stock pool but not in the main fishing lakes.

Maybe he/she stumbled on this fishery during exploration or maybe at one time when not observing he/she did follow the parents but certainly their was no teaching from this nest.

Two differing stories from the same year and same source of food but differing nest locations.

I will tell you over the years this is one of my best observations and individual records and it took me until 2010 to find it. I wanted to repeat the study last season but the nest overlooking the fish lakes failed and may do so this year.

Jackdaw infestation another story maybe - I am going down today to discuss this with the fishery manager before the season starts as we already have ospreys back.

Anyone have thoughts how will we get rid of the jackdaws who appear to be starting to nest in the lower outside of the nest cone.

Hello ValC - This is the same observation I got from nest 2 but with Nest 1 directly over the fishery lake it appeared a differing story and in general is as you say.

Many Thanks and Interesting looking forward to your magnificent pictures and reports from your nest - I have your web site favourited.

Thanks to Valmc and Keith from me for their observations. Chloe tells me that this subject has been debated before and the link I was shown yesterday certainly indicates that Mr. Meinertzhagan and his observations have already been challenged. If I can try and work through a logical explanation of all of these observations - if anyone spots a fault in my logic please say so - 1. Young ospreys do not need a parent to teach them how to fish - if this was the case then none of the fledglings translocated to Rutland (and indeed anywhere else in the world) would have survived. 2. It therefore follows that the ability to catch fish must be (as Chloe says) innate. 3. I hope that most forum users are agreed that ospreys (particularly young fledglings) are 'curious' and - here is where Keith's observations are useful - if their male parent often fishes very close to their nest and they are able to see the hunting process, then they observe, and may follow the male and even attempt to imititate the male's 'behaviour.' Does this interpretation fit what published 'scientific' evidence we have and also other observations (including Keiths)? I think that there is a big distinction here between 'learning' and 'teaching.' They may learn, but surely, they are not taught.

CRINGER

Your logic seems good and fully agree with 1 and 2 but I have one little issue with 3 and the observation I posted.

As they all hovered over the lake he would go into a dive but never came out with a fish which was strange because he only ever took one dive and always caught the food on tap.

What was he doing here any explanation - I agree the young can copy him and learn but it appeared he was teaching by this action. He never fails to catch on a dive. This is unique case because the juveniles had a front living room window over the fish lake. I said earlier I was also flabbergasted at this.

Hi Keith. I have NO explanation for what you observed. This appears to be moving into the realms of a conscious decision by the male to TEACH.

I said on the EJ thread that I strongly believed in the pooling of data. I would like to reciprocate and share some of mine. I spent many a happy (and very cold) hour just after dawn at Rothiemurchus Fish Farm watching Ospreys attempt to take fish there. I seem to recall (but am not certain and don't want to be accused of libel) that you intimated on another thread that identifying individual ospreys wasn't your strong point. I attempted to identify individuals at the fish farm by drawing diagrams of where they went - if they perched - as they often did after an unsuccessful dive I would note where they perched. I found that often after an unsuccessful dive they had obviously expended a lot of energy in breaking the 'surface tension' and getting out of the water, and, after a swift 'dog roll' would go and perch nearby - presumably to help dry their feathers. I am happy that I had a handle on most birds on most mornings - I had no idea which nest where they were from - unless they were successful, in which case they would tend to make a 'beeline' compass direction for the nest they were from - and did not have a clue whether any of them were the same individuals I had witnessed the previous day - again, unless they were successful and set off 'home' in a particular direction.

I was interested in success rate - the number of dives the average osprey makes before he takes a fish. The books suggest somewhere between 1 in 3 or 1 in 4. Looking at most ospreys, and being able to identify who was who I could not disagree - the mean appeared to be about 1 in 3.5 - although some were much better than others. I kept a 'tally sheet' of successful or unsuccessful dives, but soon realised that I needed to introduce another category, apart from S or U. That was 'A' for aborted. I saw some Ospreys hovering, then diving, then at the last minute aborting their dive. Changing their mind at the last minute and pulling up, milliseconds before touching the water. Quite quickly 1 osprey in particular caught my attention once I had introduced 'A' - he had 12 consecutive As in a row. Obviously, I thought, not a very good provider, but then dive number 13 produced a fish - and away he went. Over the next week I saw an osprey on 4 occasions exhibit the same sort of behaviour, which was unlike most of the other ospreys - many As, no Us, followed by 1S. I am pretty sure it was the same male. I changed my mind. This guy knew what he was doing. He wasnt going to waste valuable energy hitting the water and then having to get out unless he was 100% certain he would get that fish. Hats off to him. More evidence that though we talk about Ospreys in general and Scottish ospreys in particular, that really there are collections of individuals that differ?

My estimations of successful dives is on par with yours some not as good as 1:3.5. However nesting over a fish farm lake this particular male was successful on every attempt if the water was calm. If it was not he would just fly a few hundred meters to the stock pool.

The manager there is Osprey friendly and has built a pool with less large fish - easy to handle for the Ospreys.

I enjoy the reading of your observations at Rothiemurchus Fish Farm.

I have a new question. Today a male osprey returned to LG and on his return appears to have seen off a rival that had been there for 4 days. Then he went fishing and immediately gave his catch to his female. I think he deserves the adulation he has received on the posts. But........... what about the male he ousted? Blue XD. He has been described in various posts as 'useless' and inexperienced. That may be true...... but I wonder???? If you accept the Darwin / Dawkins theory that a male of any species is driven to leave as many of his offspring as possible in the future then is it not just possible that Blue XD has achieved this? What is the betting that the first and/or second egg that EJ lays, will have been fertilised by him? What effort did he put into the relationship? Not much by way of food provision - he was very active bringing nesting material - but then why not? If he is at the nest site he is there to 'guard' his fertile female. Taking the argument a stage further......... if I wanted to leave as many of my osprey genes as I could to the next generation then I would behave as Blue XD has - find a fertile female, feed her as little as I could get away with, guard her the best I could, then when the 'rightful owner' of the nest comes back I would get out of there pdq without putting up much of a fight, try and find anbother fertile female without a mate and repeat the whole process over again and leave someone else to expend all that energy bringing up my chicks. So, I pose the question - was he inexperienced? or was he actually 1 'pretty smart' experienced Osprey who had read Darwin's books?

CRinger I agree with you. It seems to me that Blue XD's behaviour was indeed in line with what you might expect from a promiscuos male.

Odin may well have won the war but may end up bring up one or two chicks that are not his own. I think that is called a Pyrrhic victory.

In 2004 Henry was accused of playing away when he was absent from guarding EJ for very long periods. As you probably know Henry was close to sainthood in the osprey world.

I think that Richard Dawkins would be extremely proud of Blue XD

If people have not read The selfish Gene  by Richard Dawkins then now is the time to do so.