If the sides are gently sloping, it will be used by small birds for bathing and drinking, and many of them will attract toads, frogs, newts and quite a few aquatic and non-aquatic insects. Last year, my pond attracted some Grass Snakes and also an unwanted visitor, a Heron, which cleared it out of not only Show-Class winning Goldfish but also any others which it spotted, leaving me just a few black youngsters from a late spawning.
Herons eat mostly fish but will also partake of amphibians and small mammals plus small quantities of reptiles, insects, crustaceans, molluscs, worms and small birds.
They fish mainly at dusk and dawn, which is why they are rarely seen in gardens and garden ponds. Understandably, Herons will respond to a garden pond just as Blue Tits are attracted to a nut feeder. They will come into gardens if the weather is particularly severe and natural hunting become frozen, they will also come for an easy meal at the start of the breeding season. Young herons when they leave the nest in June/July have to teach themselves to fish and they are attracted to small garden ponds because they tend to offer easy fishing.
There are several ways in which a garden pond can be made less attractive to Herons but, remember when you are trying to 'Heron proof' your pond, you could also be denying other wild life the use of the facility.
Several things can be done in the endeavour to stop Herons fishing your garden pond, bearing in mind they have requirements for ideal fishing. Remember these when building a new pond and/or landscaping around an existing one.
1. Unimpeded access to water surface
Solution – netting can be a cost-effective, heron-proofing bearing in mind that the mesh must be smaller than 2.5cm (1 inch).
The net must also be kept taut to prevent the Heron from weighing it down.
Remember, a Heron can put its neck through mesh which is 5cm (2 inch) and has a reach of 60 cm (about 24 inches).
Making a barrier constructed of polypropylene twine , or an obvious ribbon, could make an alternative. This must be at the very edge of the pond to stop the Heron landing inside the fence.
2. An area of water must have a good all-round view, they need to be able to see danger
Solution – grow tall shrubs or emergent plants at the open edges of the pond, concentrating on the edge used by the Heron on arrival or departure. These plants will also benefit the fish and any wildlife in the pond.
3. Gentle sloping banks – Herons like to wade into the water from the bank to fish.
Solution – when building from scratch, consider building vertical sides. Very careful consideration is required before doing this as you have to provide means of escape, for example, if a hedgehog falls into the pond. The sides need to be reinforced to prevent collapsing and are far less attractive.
4. Water levels close to the top of the bank will make for easier fishing from the edge
of the pond for the Heron.
Solution – combining low water levels with vertical sides, at least 60cm below the edge.
This is not a very attractive solution!
5. Calm and clear water makes the fish easier to see, both for you and the Heron.
Solution – a spray of water (fountain or waterfall) will make seeing fish more difficult, but is unlikely to protect the whole surface area of the pond unless the pond is small and the disturbance is very vigorous.
6. Water free from vegetation of any sort leaves fewer places for the fish to hide
Solution – an abundant growth of vegetation provides natural cover for the fish and oxygenates the water. If this is not practicable, or as a seasonal cover, use artificial lily pads secured around the edges of the pond. These will deter the Heron, who will not be able to walk on them and, hopefully, give up and fly off.
7. High fish populations
Solution – there is very little that can be done about this other than either increase the size of your pond or decrease the number of fish. Obviously, the more visible your fish are, especially at spawning time as they chase around the pond, they become more irresistible and easier to be caught by the Herons.
There are several methods that can be employed to scare Herons.
a) Audio scaring. Audio scaring may not be socially acceptable in an urban area, particularly
if it is a combination of gunshots, gas cannons, bird alarm call or other sharp noises.
b) Visual scaring devices. Windmills, flashing lights and silhouettes of birds or prey.
Some work better than others, but each has a limited effectiveness, could be for a
couple of hours or a couple to three weeks. An improvement may be established by moving
them around periodically or in rotation.
c) The most effective solution is human presence, especially early in the morning;
this also increases the effectiveness of other devices. A human shape, or scarecrow if you
like, suspended over the pond is particularly effective. It can be removed when the
garden is being used socially, but acts as a deterrent in the early morning or at dusk.
d) Model herons. It has been suggested that these act as deterrents.
NOT SO, even when they are moved about regularly. When food is abundant, Herons
prefer to hunt or fish in groups. The presence of other Herons means that they don't have
to be fully alert to danger and can spend more time feeding.
There is no 100% effective solution to prevent herons entering your garden and helping themselves to a feast of your prized fish. Even the most effective netting can be breached if not maintained to very high levels. The only gentleman that I know that has been successful has a totally 'net-encapsulated' garden, not even a sparrow can get in!
As I have tried to point out, all fish-eating birds are extremely ingenious and will find a way to exploit any unprotected food source. Our own, human presence is the only effective way of scaring them away, but we cannot stand around 24 hours a day, every day, just to frighten Herons.
They are a protected species at all times throughout the UK under the Wildlife and Countryside Act 1981 with fines or prison sentences available for anyone killing or attempting to kill one. So you can't shoot them either.
So we have to live with the problem and beat them the best way we can.
Have you any thoughts about how to stop herons attacking your ponds and enjoying your prized fishes?
As an afterthought – in Holland several years ago, we even saw Herons plunge fishing in one of the many little fishing harbours. I give up!!
This article was originally published in the C.A.D.A.S. magazine
Last updated March 2007