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Read by Dave and Charley
It is not just our seabirds that have to care for their young on Alderney, there are many other species around our island raising a family at this time of year. Most other bird species raise their young in similar ways to our seabirds.
Rock pipits make nests out of vegetation in gaps under rocks and in tall grass; including on Burhou
Cuckoo
But one species is very different, the cuckoo. Cuckoos are known as nest parasites, this means that instead of making their own nest and caring for their own young they actually infiltrate the nest of another species. Once they have scared the adult birds off their own nests, particularly meadow pipits and dunnocks, they will lay an egg of their own in the nest. This egg will mimic the look of the resident species’ eggs. The cuckoo chick will push other eggs out of the nest once it hatches or outcompetes the resident chicks for food. This means the meadow pipit or dunnock chicks unfortunately die whilst the adults unknowingly raise a cuckoo chick instead.
Pipistrelle bats are very small, weighing only 3-8g and with a wingspan of 20-23cm. But they are mammals and raise their young in the same way most mammals do. They give birth to live young, just one but very rarely two at a time, but they are just the size of your thumbnail when they are born. For the first 4 weeks of their lives they cling to the underside of their mothers, feeding on milk and even holding on whilst the mother is in flight. After 4 weeks the young can fly but take another 2 weeks to learn to forage for themselves.
Pipistrelle bat
Not all species are good parents, insects like moths, butterflies and dragonflies do not care for their young but just lay eggs on plant species that the larva will feed on when they hatch.
An emperor moth lays its eggs on a plant that the newly hatched caterpillars will eat, but it doesn't look after the eggs
ECOLOGIST'S UPDATE
We went back to Burhou on Sunday overnight to Monday in order to monitor a few species. This included doing some puffin watches. At this time of year the puffins are busy catching fish and bringing them back to their puffling in the burrow.
A puffin on the water with sandeels
Seeing them come in to land can be very difficult as they fly so quickly, but we were able to confirm over 12 burrows that had chicks in. This is very promising as they were seen in just a few hours of monitoring. Next week we will go back to Burhou to do some more puffins watches and try and confirm some more burrows with chicks in. The video below shows our view of puffins 'wheeling'.
Wheeling - when puffins fly past their breeding grounds and over the water in circles to check the ground is safe for them to land on before they enter their burrows.
Why do some sea birds lay only one egg?
Birds that nest in burrows, like puffins or storm petrels, or birds that are very big, like gannets, feel like they can offer more protection to their eggs due to location or size. Therefore, by only having one egg they feel safe enough to dedicate all their time to successfully raising one egg/chick. Birds that have more exposed nests that they aren’t big enough to always defend have more eggs to try and increase the chances of at least one surviving.