Some owners of pet birds are surprised to find oval white chalk plates washed ashore as they know them from pet shops where they are sold as supplementary bird food. The plates are backbones of cuttlefish. Cuttlefishbones stay adrift for months and reach the Waddensea originating from France or England. Seabirds like pecking the cuttlefishbones and leave their bill marks on them. Usually the bones stem from the Common cuttlefish which may reach 40 cms in size. Smaller backbones may be from rarer southern cuttlefish species. Living cuttlefish are hardly ever found in the Waddensea, the reason is unclear.
A hovering moth resembling a hummingbird and rushing from flower to flower is the Silver Y. This medium sized grey moth belongs to the large family of owlet moths and bears a Y-shaped mark on each forewing. The Silver Y is active at day and night and can be seen everywhere at the moment. The species winters in southern Europe and flies northward in spring, sometimes up to Iceland. The hungry caterpillars eat everything green (except politicians) and can develop in two generations until autumn. Then up to four times the number of moths that came in spring fly southward again for hibernation. Like the migratory birds the Silver Y is an eternal wanderer.
A furry bunch of brown hairy caterpillars is a typical find in coastal saltmarshes at the end of may. These are the caterpillar nests of the thermophilic Ground lackey moth. Only about 20 years ago this specis has reached the Waddensea coast - possibly arriving from english salt marshes. The caterpillars spend their first weeks sociably on a commonly spun silk carpet. They feed on different herbs like Sea aster, Sea arrowgrass or Sea plantain. The older caterpillars live individually and tend to develop blueish markings. The adult moths fly in july and leave egg clusters on plant stalks, from which new caterpillars hatch in next spring.
In some years starting from march strange fuzzy animals can be found at mussel beds or washed ashore. They are 4 - 10 cms long and have a smooth foot underneath the whole body which marks them as slugs. The head bears four tentacles, the back is covered in dozens of fringes. They harbour gut appendices which store nettle cells that origin from the prey of the Anemone slug: Plumose anemones and Mud sagartias. The Anemone slug occurs in different colour variations, is adult in spring an lays spiralled gelatinous egg strings.
When sea temperatures fall in winter, masses of heart urchins have to pay the debt of nature. Especially along sandy coasts where numerous urchins have colonized the seabed during summer hundreds or thousands of these fragile shells are washed ashore. Usually they have lost all spines and often the shells are broken. Looking from above this shell looks slightly heart-shaped, hence the name of this burrowing echinoderm. Underneath the globular body is the mouth opening. Nutrituous soil particles are consumed while the heart urchin digs its way below ground at a depth of about 10 cms - filling the ecological niche of earthworms on land.
November is the time when large fishes or other rare marine creatures tend to strand on beaches. Among them were several Lesser octopuses this year. But sun- or swordfish also tend to be found in november. The sinking sea temperature causes the stranding of cold sensitive species that have entered the North Sea during summer. Already during the 1970s the Lesser octopus was temporarily present in the Wadden Sea. It is not a "southern" but a cold senisitve species. The shallow Wadden Sea cools faster down than the deeper North Sea - a natural factot excluding sensitive species. Time to look for rare finds on the beach!
Early spring is the right time to look out for Crystal jellies. This jelly fish with characteristic lines on its umbrella has never been found north of the Elbe estuary. May be this year? But reports from western and eastern Frisia are also surprisingly rare as the species is regularily reported from Spiekeroog in september. Watch out for it!
In a few days three transmitters of this type should be washed ashore in the WaddenSea. On october 15th they have detached themselves from the back of harbour seals on which they had been fixed be researchers of the veterinary highschool of Hannover. The devices recorded during ten days 800 times per second(!) the seal's movements to help analyse their hunting strategies at sea. In case you come across one of these transmitters please contact immediately: firstname.lastname@example.org
In summer it may happen that tourists get "stung" while bathing in shallow waters of the North Sea. The stings do not itch and the moderate pais eases quickly. The culprit is the sea louse, a 5 mm long marine isopod searching for food in the surf zone. The small animal bites anything that seems digestable - including bathers. Its scinetific name translates as "beautyful Eurydice" and is derived from the greek myth of Eurydice, who sank back into underworld - just like the small isopod which sinks exhausted back to the seafloor after quick circling swims at the surface.