Wednesday, 3 July 2019

Saturday and Sunday 29th and 30th June and Cranes

Sedge Warbler (c) Bark

One of the hottest Saturdays that I can remember for quite a while, by Sunday the weather  was cooler but still sunny and pleasant. Although we are getting to that time of year that many birders refer to as the “doldrums” there was still much to see and to comment on.
Lesser Whitethroat (c) Bark
I am now able to report once again on our regular pair of Common Cranes, perhaps one of the worst kept secrets in Oxfordshire! Sadly, they failed to raise any young again this year. We monitor their breeding progress by observing their behaviour which indicates when they are nesting, when they are incubating and when they are protecting a chick or chicks away from the nest site before fledging.
"Our" Cranes (c) Bark
The season started well with them arriving within a day or two of previous years, courtship behaviour and mating was seen, and we were hopeful that this year they would finally raise a chick to full fledging. We were mindful that last year their chick was just three weeks away from flight and independence when it was predated.
Nest and infertile eggs. (c) RSPB
All progressed as normal with the birds taking it in turns to sit and we know from other sites how long the incubation time is and when we could expect to see them moving the young away from the nest site. The sitting behaviour seemed to progress for thirty-five days and we hoped that they had hatched young and were keeping them close to the nest site. We finally saw the two individuals out together on Greenaway’s and quickly realised that they had no young with them. RSPB staff went out to the nest site and found that there were two eggs there that had failed to hatch. Crane experts state that they would never have sat on infertile eggs for so long and suggest that these two eggs were the product of a re-laying after an initial failure. We don’t understand why that happened but have speculated that at some point the eggs may have got chilled, perhaps the first clutch was predated.

Interloper and our bird challenging (c) Bark
When the birds first returned in addition to our regular pair of Cranes there was another pair in the vicinity, which caused some conflict. During the presumed second incubation period, yet another unpaired female Crane was present for at least a couple of weeks, near to and over the nest site on several occasions. On two occasions I saw “our” female chase off the interloper. It may be that this disturbance was enough to cause the eggs to get cold or perhaps there was some other reason for their infertility. We will never know quite what happened but hopefully it will all come right next year.
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The Cranes are still present on and around the moor and are seldom more than a few metres apart at any time. A careful scan of the northern edge of Greenaway’s will often reveal them, their necks stretching up above the long grasses where they are feeding. They are likely to stay around now for at least another month before “migrating” back to Somerset.
Two newly fledged Marsh Harriers (c) Bark

On a more positive note our resident Marsh Harriers have once again bred successfully and on Sunday morning we watched four newly fledged chocolate coloured being called up from the reedbed willows to have food dropped for them by one of the  adults. The male is now hunting frequently over Closes and Ashgrave.
male Marsh Harrier hunting over the closes (c) Bark

There are still Common Terns in different stages of development out on the raft, from tiny balls of fluff to just about flying. The adults are bringing in plenty of fish and one was seen last week to bring in a tiny pike for one of the larger chicks. There are abundant fish in the ring ditches, and I assume in the River Ray.  Staring into the water close to the pumphouse we saw abundant fry and below them some very large Perch and Rudd.
Fish by the pump house (c) Bark

Evaporation is starting to draw down the water levels in front of the first screen and areas of mud are starting to be exposed. On Saturday the first Green Sandpiper of the year was seen out there. As the waders start to return now the solstice has passed, we can expect to see more. On Sunday seven black tailed Godwits came up off the flood field and flew over towards Big Otmoor, but the grass out in the middle is now totally obscuring the scrapes and so we were unable  to relocate them.
Blackwits (c) Bark

There is a male Sedge warbler that has taken up residence along the bridleway just a bit past the bench. Just as last year it is a fearless and frenetic individual that belts out its song at point blank range whilst clinging to the old reeds that still stick up above the new growth. Just as  last year he looks likely to become the most photographed bird on the moor.

Photogenic Sedgie (c) Bark

The warm sunshine has brought on the insect life rapidly.   

There were large numbers of Meadow Brown butterflies along the path to the second screen with a smaller number of the more restless Ringlets amongst them. The brambles are just starting to flower providing a rich source of nectar and pollen for all the insects. There were three different Long-horned Beetles spotted along the Roman Road on Saturday. Both Banded and Beautiful Demoiselles were to be found beside the ditch.
Banded Demoiselle (c) Bark

Stop Press. Tuesday evening Quail calling from the MOD land.

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