The grey heron

Some time ago I was sitting on the bank of a pond here in the neighbourhood, when suddenly a grey heron (Ardea cinerea) landed about fifteen metres away from me. The bird didn’t seem to care about me at all and started preening vigorously. He or she twisted and turned in all sorts of ways, which resulted in some beautiful pictures. It was special to experience this from so close. Normally grey herons fly away immediately when you approach too closely and they don’t generally land next to you. A little later it became clear to me why this heron was looking for me. Fishermen regularly sit at that spot and sometimes there is a fish left for the heron. Unfortunately for the heron, that wasn’t the case this time.

Sixty-six species

The grey heron is the most common species of the heron family (Ardeidae) in the Netherlands and Belgium. Worldwide this family contains sixty-six species, eight of which occur and breed in our country. After the grey heron, the great egret (Ardea alba) is the most common. A species that is listed as a vagrant in my old Peterson’s bird guide from 1976, but now there are about five hundred and fifty breeding pairs in the Netherlands and in winter many thousands of individuals are counted that come here to spend the winter or that stop here during theit migration south. There is also a smaller species, the little egret (Egretta garzetta). In the Netherlands the little egret is a lot rarer than the great egret. After the first breeding pair in the Oostvaardersplassen in 1979, this species can now also be counted among the native breeding birds. The number of breeding pairs nowadays is around a hundred.

More herons

The other relatives of the grey heron that breed in the Netherlands are the purple heron (Ardea purpurea), Eurasian bittern (Botaurus stellaris), black-crowned night heron (Nycticorax nycticorax), little bittern (Ixobrychus minutus) and western cattle egret (Ardea ibis). The last three species are considered breeding species but the number of breeding pairs of night heron and little bittern are currently at most fifty and that of the western cattle egret is about five. There is also another species of heron that occasionally visits the Netherlands, namely the squacco heron (Ardeola ralloides), see the adjacent photo.This is a very rare species that can be seen in our country in very varying numbers year on year. And to complete the list of herons there is the very rare green heron (Butorides virescens) that occasionally turns up in our country. This North American species was briefly spending time in the Amsterdam area in 2006 and 2007 and appeared in Zaandam in early July 2009. Since then, no green heron has been seen in our country.

Overconfidence

Blauwe reiger / Grey Heron (Ardea cinerea)

The grey heron is a real lover of meat and fish. All kinds of fish, but also amphibians, small mammals such as rats, mice and moles, young ducklings, nothing is safe from the heron. They usually eat prey weighing more than 100 grams and sometimes more than 500 grams. There is also a known case of an adult heron that managed to catch and swallow a sea trout weighing 680 grams. Sometimes there is a bit of overconfidence and the prey is a bit too big. Especially if the heron has actually impaled it with its dagger beak. In the adjacent photo a grey heron that I saw standing in the middle of a meadow with a fairly large fish. Eventually he managed to get the fish loose and left it in the meadow uneaten.

Frightened by many a pond-owner

Herons also like to eat frogs and toads. In the video below you can see him in the morning mist at our pond and he has caught a big frog. Not everyone is happy with a heron visiting the pond. Because herons also fish out the smaller gold and koi carp. You can’t blame the bird if the food is presented to him so easily. We don’t mind a heron visiting our pond every now and then. In fact, over the past few weeks a grey heron has been visiting our pond regularly and has caught at least five frogs.

Star jelly

When a heron has eaten a female frog or toad, something special happens. These females have special glands in which the jelly-like substance is produced that surrounds the eggs. You probably know it from frogspawn. The heron cannot digest this substance. In addition, this substance is very hydrophilic, which causes it to swell in the heron’s stomach. The bird will then vomit the gelatinous mush. See the photo on the right. In the past, people thought that this substance came from falling stars and that is why they called it star jelly. In the Netherlands it is also known by the name of witches’ snot, because in earlier centuries people thought that a witch had left it behind. But it has nothing to do with stars or witches. Incidentally, it is not only herons that vomit this stuff. Other predators that eat amphibians also produce star jelly, such as storks and buzzards. And also mammals such as foxes and mustelids

Wintering

I remember from the past that there were far fewer grey herons in winter than there are now. My Petersons confirms that only a small number of herons wintered here. The vast majority migrated south in autumn to return in spring. Nowadays this is different. You see the grey heron all year round. Of course, climate change also plays a role here. The winters are so mild that ditches and streams hardly freeze over anymore. The heron can therefore find enough food. And when it gets so cold that there is nothing left to eat, they still migrate south. A phenomenon that we also see with for instance storks and lapwings.

Colonial breeders

Grey herons are true colonial breeders and make their nests high up in trees. The number of nests in such a colony can be more than two hundred! And those colonies are certainly not all located in a nature reserve or something. No, you can also find heron colonies in the middle of Amsterdam. The Artis zoo is home to one of the largest colonies in the Netherlands with more than one hundred and twenty nests. Not so surprising, because just like the heron that sat next to me, these birds also have their eye on fish. No fish for them of course, but as food for the penguins and gannets in the zoo, among others. Their stay in Artis is not without danger, because every now and then a lion also takes one. Elsewhere in our capital city, such as in the Amsterdam Forest and the Sloterpark, around one hundred nests can be found. Herons reuse their old nests, so that after a few years some grow to a considerable size. The male brings in material and the female makes a nice nest of it.

Powderpuff

By the way, you have to be careful when walking under a heron colony. An umbrella, against the large amount of poop that is draped over the edge of the nest by the young, is sometimes useful ;-). The young birds in the nest do not spare each other either, they usually look very disheveled and dirty. The grey herons themselves do not worry that much about getting a bit dirty. They take very good care of their appearance and have their own cosmetics with them. They have special feathers on their chest, so-called powderpuff feathers. Unlike other feathers, these do not fall out, but continue to grow. However, they do not grow bigger, because the tips of these feathers are very fragile and can easily pulverise. The heron rubs its head along these feathers to collect the powderpuff and then applies it to the feathers. The dry powder absorbs the dirt, but the beauty ritual is not over yet. Because the heron then combs its feathers clean with its toes. The inside of the middle toe has a serration like a comb. This is how the heron keeps the feathers in optimal condition.

Four to six eggs

The grey herons start looking for their nesting sites in January, especially the wintering ones are already sitting on eggs at the end of that month. They lay four to six eggs that they hatch together in 23 to 28 days. After hatching, the young are fed for a month. A good three weeks later, they can fly and start looking for their own food. They then continue to hang around the nest and sometimes they’re fed by their parents. About nine weeks after they have hatched, they leave the parental nest for good.