The current beautiful but brutally cold weather we are experiencing is lethal for many tiny creatures but also larger birds including our grey heron (Ardea cinerea). Cold spells such as the current one can result in the death of a large proportion of our heron population as they are unable to fish for their normal food supply when water courses freeze over.
Statuesque grey heron on Cambridge Science Park
The grey heron is a member of the family containing bitterns and egrets and aswell as being the largest European heron is one of the largest UK birds. They stand almost a metre tall with an average wingspan approximately 185cm and feed predominantly on fish and other creatures, in or close to water, such as frogs and other amphibians, but have been known to take small mammals, reptiles and insects.
Herons are considered to be among the more intelligent birds due to their ability to hunt and catch such a wide range of prey. One individual in Histon has recently exemplified this intelligence in an unusual and amusing way. It arrived in my friends garden looking very sorry for itself a few weeks ago at the start of the winter weather. My friend, being a thoroughly decent sort, gave it some fish from his freezer after which the heron decided to loiter. After several free and very easy meals of frozen pollock it took up residence in the garden and when the stipulated mealtime was not observed to its full satisfaction would sidle along to the door and tap on the glass with it’s bill to summon the next course.
The Histon heron
Waiting for a snack…
…and tucking in to a pollock fillet…
…then retired to a nearby vantage point for some post-prandial relaxation
As well as being sizeable birds heron can be stealthy and are extremely efficient fishermen. They catch smaller fish and eels in their bill but as you can see from the photographs the bill is a fearsome weapon and is used to spear larger prey. I once encountered a heron pecking at a prey item on the bank of the Lode at Wicken Fen, as I approached the heron flew away and I found an enormous pike on the riverbank, approximately 2 feet long (I don’t know if a heron would be capable of catching and killing such a big fish) and it had made a surgical incision running from top to bottom immediately behind the gill and had been busy extracting the entrails.
Heron are not migrants to or from the UK but they have been known to cross the English Channel and turn up in France and the Iberian peninsula. They have various common names including the ‘hernshaw’ in Lincolnshire, the ‘marshmens harnser’ in Norfolk and a ‘shiterow’ or ‘shiteheron’ thought to originate from the herons habit of defecating when disturbed prior to take off!
So if your pond is overstocked with fish in the freezing cold weather and could use some thinning out why not spare a thought for the struggling heron and break the ice so he can refuel and stave off the cold.