Leicestershire and Rutland Wildlife Trust

Thursday 3 June Another picture of 02(01) Photo: Terry Tew, 26/5/04

This week we received another great picture of the latest Osprey arrival at Rutland Water. Bryan and Terry Tew found the bird with a roach on one of the dead trees beside the path to the hides on the Lyndon Reserve. More details about 02's re-appearance at Rutland Water were published last week. Incubation - just a few more days to wait The long process of incubating eggs should soon be coming to an end and male 03(97) and female 05(00) may soon be hearing sounds from the egg or eggs and then seeing the first signs of hatching. As we monitor the nest we hope to see tell-tale changes in their behaviour and very much hope that by next week we will have some good news to report. So it's fingers crossed for good weather in the vital few days when the chicks emerge weak and helpless from the eggs.

Other Osprey sightings Today, just as this webpage was about to be published, a pair of Ospreys (male and female) arrived on the artificial nest in Manton Bay. There were lots of fishing boats in the vicinity and the female looked very nervous. Before we could get close enough to read ring numbers, the pair floated away to the north above the Visitor Centre. Other un-paired male Ospreys are still in the area and are often seen circling high in the sky above various parts of the reservoir. 08(97) can often (though not always!) be seen in the evening eating fish on perches near the Fishponds. 06(01), the second female to breed last year, has not returned. Her mate, 03(98), is still occupying last year's nest site but he spends longer periods of time away from the nest, probably looking for her, or for a replacement female. We do not know what has happened to 06(01) the female who previously broke every rule in the osprey book, (details are here).

The female 05(00) sitting and male 03(97) in close attendance during day 17 of their incubation.

Yesterday real changes in adult behaviour began to occur. In the morning the male 03(97), rather than flying up to shepherd the intruding male Osprey away as it flew over the nest site, flew onto the nest and spread his wings, "mantling" defensively over the incubating female, 05(00) . Something was definitely up. During the day both adults were seen obviously peering down into the nest cup, heads cocked from side to side. During the night, the night-vision equipment that has been used so effectively during the previous 37 nights, revealed the female was doing all the incubation but was very, very restless.

Just before 5am this morning , Field Officer John Wright and volunteer John Tipler saw the male fly up to stand beside the female on the nest rim and look down with what seemed like real interest. He took off and flew purposefully away towards Rutland Water. Less than 10 minutes later the two Johns heard the distinctive call of a displaying male high above them. He was carrying a fish and repeatedly diving and soaring closer and closer to the nest. Was it one of the unpaired males?

Soon the bird descended and they were able to see the white ring and distinctive clean-cut plumage. It was 03(97) returning to the nest with a perch but, very unusually, he was displaying first overhead. It was just as if he was punching the air and saying "YESSS!!" said John Wright, convinced at that point, that there was definitely some new life hidden deep in the nest cup. During the next ten hours the adult behaviour was not exceptional. Perhaps we had claimed hatching too soon? True, for the first time for several weeks the female spent all the time on the nest rather than letting the male take over incubation duties. And also there were several occasions when Osprey intruders floated in quite close and again the male joined the female on the nest adopting a very defensive attitude. Then at 3:30pm the clincher came. The male brought in another fish - a roach this time. Having eaten some of the head he delivered the rest to the female who began to eat it standing on the rim of the nest. Then she delicately tore off a small piece of fish and bent forward with it down into the nest cup, clearly offering a chick its first meal. The action was repeated seven or eight times. Often the piece of fish was still in the female's bill as her head came up and she would toss it into her mouth before tearing and offering the next tiny fragment. All the while the male was sitting close by, watching the process with interest. At least one new Rutland Osprey chick has most definetly hatched!.

The female bending towards the chick or chicks while the male looks on. 18:00 on 6 June 2004

Thursday 10 June We can't count heads... The breeding pair have re-established the parenting roles that we observed last year. The male (on the right in the picture) has already upped the fish supply and the female now remains on the nest for almost all the time. During incubation she would fly to a nearby branch to eat and the male took over incubation duties. This week she eats on the nest itself and increasingly we are seeing her tearing off fragments which she presents to whatever is down out of sight within the nest cup. Watching very carefully we try to work out whether she is presenting the fish in more than one location, but this is an uncertain way of determining how many chicks there may be: you can't really count your chicks until they show their heads above the rim of the nest. ... but we can count fish! During the 38 days and nights of the incubation. the monitoring team kept careful notes of how the adults were behaving. In particular we observed a total of 90 fish being brought in by the male for the two birds to eat. Tim Mackrill has been analysing these data and two of the surprising (to us!) results are shown in the charts below. They concern what fish were brought in when.	The two adults on the nest on 8 June.
Firstly there is a very high proportion of roach and far fewer trout than we expected. Rutland Water is stocked with trout, but roach must be much easier for the male to catch at this time of the year. Why is this? Will it change as the summer progresses? Any comments or suggestions about this would be most welcome.	Secondly we were surprised when most fish were brought in. We were under the impression that Rutland Ospreys are easiest to see fishing in the early morning. We expected that another popular time was the evening after a quiet spell in the middle of the day but we were very surprised that so many fish (nearly 40%) were brought to the nest between 4 and 8 pm.
Species of fish caught by 03(97) during the 38 days of incubation	Number of fish caught in hourly intervals during the 38 days of incubation

It's two!

Yesterday afternoon came confirmation of the news that we had suspected for the last couple of days - there are two (at least ) Osprey chicks in the nest.

Several volunteer monitors had ben convinced that the female had been presenting food into two positions in the nest cup, but the first sighting of the tops of two small white heads was by Jan and Alan Taylor, followed soon afterwards by Richard Foers.

Otherwise life on the tree top has been fairly quiet this week, with the male bringing in a good supply of large fish and very few intrusions made of the nest by avian intruders.

Co-ordinated watches

Now that the rigours of 24-hour nest monitoring are over, we have time to undertake more careful observation of the other males that are in the vicinity. On Monday morning from 5 to 9 am and again on Tuesday from 4 to 7:30pm, teams of watchers were at key positions around the reservoir, looking out for perched or fishing Ospreys. The team communicates by radio so it enables us to make a total count of Ospreys present and to effectively follow individual birds as they fly from one part of Rutland Water to another.

On both occasions the teams were able to see fish being caught by three of the unpaired males: 03(98), 09(98) and of course 08(97). On both days the latter took his fish to eat on the Manton Bay nest, in full view from the hides of the Lyndon Reserve. So including the breeding adults, we can say confidently that on both days there were only 5 adult Ospreys present. This, of course, raises questions about what has happened to the other males identified earliet this year. If they are not at Rutland Water this week, just where are they? Co-ordinated watches like this will continue each week during the rest of the summer.

Moult All birds need to replace their worn out feathers and adult Ospreys moult throughout the year, though they suspend the moulting process during migration periods. One or more flight feathers are replaced at a time and this enables the birds to replace all the feathers each year and yet retain good flight ability. This moulting process can sometimes also aid recognition of individual birds in flight. This week, Field Officer John Wright realised that 03(98), the male that bred last year but whose mate has not returned, had suddenly developed a gap in the feathers of the left wing. This has made this male easier to identify as he flies around the reservoir, though a feather will very shortly grow to replace the one that has been shed. Knowing that 03(98) has a favourite roosting and feeding tree near last year's nest site, John went to see what he could find. As well as the remains of several fish there were the two feathers pictured here. The lower feather, at about 400mm, is one of the longest outer flight feathers (primary 8). Notice how much of the upper edge of the feather has completely worn away. The smaller feather is either an inner primary or outer secondary, from the middle of the wing.

Fishermen's tales

Last week we asked for comments and suggestions to explain why the Rutland Ospreys' diet during incubation in 2004 included such a high concentration of Roach. We have been sent all sorts of answers that are now published here on a separate page, part of the Questions section of this website.

Do you agree? is there more to say? Do send us an email.

Changes at the nest

We are still often seeing one and sometimes two heads of chicks, but for much of the last few days the chicks and the adult female have kept well down inside the nest cup, probably sheltering from the gusting winds and cooler weather.

It's worth noting how the nest itself is changing colour and shape. The two pictures below show how it has changed in the three months since the male first arrived back .

Notice in particular:

the levels of the top of the nest compared with the branches of the tree;

what has happened to the orange baler twine that the male bought in on his first day, almost with very dire consequences (details are here);

the fresh green leaves decorating the right hand side of the nest - the adults have started to bring in more lining material, including leaves snatched from nearby trees;

the nest seems to be beginning to be painted white - every now and then a squirt of white can be seen fired enthusiastically upwards by the chicks inside the nest cup!

Male 03(97) during his first day back at Rutland Water.

Female 05(00) on the much enlarged and decorated nest this week

More statistics from incubation While monitoring the incubation, the volunteer team were asked to record whether the male or the female was sitting on eggs. A total of 45390 minutes' observation was recorded and during this time the female incubated for 32973 minutes (72.6%), the male for 12105 minutes (26.7%) and the eggs were uncovered for only 209 minutes (0.5%). During The male's contribution increased as the weeks went on (see the chart on the right) though it reduced dramatically in the final week, perhaps reflecting movement or sounds from the eggs in the days leading up to when we assume hatching occurred. During the observed period the male was absent from the nest site for only 6499 minutes (14.3%). This represents the time that he spent catching fish and warding off avian intruders. (Statistics compiled by Tim Mackrill)

Percentage of time for which the male, 03(97), carried out incubation in 2004

It is now clear that here are just two chicks in the nest and that they are growing very rapidly. Their heads and sometimes their unfeathered wings can be seen stretching above the rim of the nest - we hope to have pictures of this very soon. The torrential rain and strong winds of the last few days certainly do not appear to have caused a problem for adults or chicks.

Meanwhile at Piper Dam in Scotland...

Regular visitors to this website may recall that in previous years we have reported on the progress of 01(99), previously called R01. She is a black-ringed female who was tranlocated to Rutland Water in 1999. In 2001 she spent a short time in Nottinghamshire and the following year was seen breeding at Piper Dam near Dundee in Scotland.

In 2003 she laid three eggs, mating with a Scottish male, Orange ZT . All three chicks fledged successfully.

Philip Mulholland has emailed us to say that this year she and the same male produced two eggs and currently both chicks are doing well.