June 2021
Most oak trees have broken bud in Sussex now (early May), with oak flowers (catkins) bunched beneath the developing leaves. Oaks are monoecious, which means that they are both male and female. However, I have just learned that female oak flowers are fussy about where the male pollen they use comes from. Oaks are wind pollinated and the female flowers get inundated with local male pollen, some from their own catkins. But they also receive pollen from afar. Apparently, female oak flowers can reject pollen that comes from local catkins in favour of land-distant and genetically distant pollen from trees far away. That way they can avoid breeding with their close relatives, just like we humans avoid pairing up with our relatives. The result is much healthier offspring.
A dry, cold April has meant that the grass is growing slowly and meadow flowers are persisting for longer. It has been a fantastic year for violets, cowslips and primroses. However, I am worried about the lack of insects to feed the insectivorous birds. I have not heard a single cuckoo yet; these brood parasites specialise in feeding on hairy caterpillars. However, I saw my first swifts of the year about 6th May, swifts eat copious amounts of flying insects, but most insects only fly in temperatures above 10° Celsius. So swifts may be having a hard time.
I visited Splash Point near Seaford early on Friday Morning 7th May and the kittiwake colony on the cliffs was in full swing. Dozens of these cute small black-footed gulls with black tips to their wings were busily building their nests on cliff ledges. There was a pair of fulmar petrels there also. These relatives of the albatrosses and petrels spend most of their long 30 year plus lives at sea, but look for a cliff to breed on in the early summer. They are mate-faithful and usually lay just 1 egg per year.
I monitor the 46 blue tit nest-boxes at Lake Wood when I can, and this year 35 of them had nests with eggs in at the end of April. One nest had 14 eggs! The wood looked superb with carpets of wood anemones and bluebells this year. The blue tits will be aiming to time the hatching of nestlings to coincide with the development of the green caterpillars that feed on the young oak leaves, such that the insect larvae will be about 2 centimetres long and full of protein, water and other beneficial nutrients.