Each of my quarterly articles appear to be predicated on the weather and this is no exception as at the time of writing we are all experiencing a heat wave with daily temperatures of thirty degrees or more, a problem not just for us who swelter but birds that have to search for food in hard ground and also the quest of all species for water. It may indeed be a greater stress for some than the difficulties of winter. However the quarter started with an unseasonal spell of wintry weather which appeared to have caused a delay in the spring migration. Apart from the Willow warblers recorded in the last Journal, migrants that have dropped in include both the Common and the Lesser Whitethroat and a Sedge Warbler that was heard singing in the reeds of the Dulwich Park Lake. The reeds are probably not extensive enough for Reed or Sedge Warblers to set up breeding territories but invaluable for drop in posts for Spring and Autumn migrants.
A number of readers have noted the love affair on the lake between a Canada and a Grey Lag Goose that has resulted in the birth of some unusual offspring. Hybridisation is well known to occur in both ducks and geese particularly in feral groups where there is more mixing than in truly wild populations. The offspring usually turn out to be infertile which means that the species remain intact, although the appearances of the so called F1 hybrids can test the identification skills of birdwatchers.
Apart from this, a pair of Little Grebes have nested and I noted at least three families of Tufted Ducks. Kestrels have nested once more on St Peter’s Church on Cox’s Walk and Sparrow Hawks have nested in Sydenham Hill Wood. The regular piles of pigeon feathers that have been noted by the Grange Lane allotment holders bear witness to the young Sparrow Hawks likely diet.
The disappointment this year was that by the second week of May, Swifts that by then should have been here screaming round our houses, had failed to arrive. Eventually a few did turn up and have mostly been seen flying high and it was most unclear as to how many if any were breeding. Swifts have been noted nationally to be in decline and some of this has been attributed to our making our houses too posh for them to find breeding sites in our roofs or eaves. The explanation may be more worrying that there are now not enough flying insects available for breeding nourishment. Many of us will remember a time when a car outing in the summer resulted in an insect cemetery on our windscreens and this now seems a thing of the past. Road waysides are no substitute for wild flower fields and meadows which supplied the basis for much of our insect population. In Dulwich having lost our House Martin colony it would be sad if we were no more to have Swifts breeding here. An ornithological classic book, Swifts in a Tower, by David Lack has recently been republished and my view is shared in its introduction with blame being firmly laid at modern agricultural practices. To this we can add air pollution.
2017 was not a good year for our native butterflies and we are hoping for better luck this year. The extremely cold weather in April may have put paid to the emergence of some of the hibernaters such as Peacocks and Tortoiseshells and I note that our roses have been less infested with Greenfly which may be an indicator, but we will have to wait and see. However the uncut field in Green Dale has enabled the survival of Meadow Browns, Gatekeepers and Small Skippers, the so called Grass Butterflies in good numbers, which of course need the continuation of this habitat for their survival. If this habitat was to go so would they as they rarely stray from their breeding sites.
And finally as ever we have had Stag beetles, this one particularly friendly and photographed by Helen and Andrew Graham in Alleyn Road. The “antlers’ are of course prehensile mandibles which ensure imminent starvation hopefully after these males have performed their required duty. Do keep up your records both with and without photos.