Garden wildlife glossary

Plain-English definitions of the garden bird, nest box, hedgehog and bird-health terms used on Finchwold, each from an official page we opened.

Each term links to the Finchwold guide or answer that covers it, where there is one. Definitions come from the RSPB, the BTO, Hedgehog Street, GOV.UK, legislation.gov.uk, the ICO or the Bat Conservation Trust; the pages are listed at the end. For questions rather than terms, see the knowledge base.

A

Aflatoxin

A naturally occurring toxin that, the BTO says, can contaminate peanuts. It is why both the BTO and the RSPB ask for good-quality peanuts from a reputable source, with no sign of mould. See are peanuts safe for garden birds?

Avian influenza

Bird flu. The BTO lists a swollen head, watery droppings and neurological symptoms as signs. GOV.UK says reported dead wild birds may be collected and tested for bird flu. See what to do with a dead bird in the garden and sick and dead birds.

Avian pox

A bird disease that, in the BTO’s words, “causes warty or tumour-like growths, particularly on the head, wings or legs”. See what to do about a sick bird at the feeder.

B

Bat box

An artificial roost. The Bat Conservation Trust describes bat boxes as “designed to encourage bats into areas where there are few roosting sites”, and notes that different bat species need different spaces. See bat boxes and garden bats.

Big Garden Birdwatch

The RSPB’s annual count of garden birds, which it calls “the world’s largest garden wildlife survey”. See common UK garden birds.

BIG Hedgehog Map

A map run through Hedgehog Street where people record the hedgehog holes they have made between gardens. See how big should a hedgehog hole be?

D

Dead hedge

A barrier built from prunings. The RSPB suggests log and stick piles, or a dead hedge, as cover and feeding spots for birds. See leaf litter, log piles and compost.

F

Fat balls and suet

High-energy fat foods for birds. The RSPB lists lard and beef suet among good foods, says suet should be eaten within seven days, and says small amounts of fat balls or suet can continue from May to October. The BTO notes some fat products are less suitable in hot weather. See fat balls and suet.

Flat-surface feeder

Any feeder where food sits on a flat surface: bird tables, window feeders and feeders with trays. The RSPB says do not use them; the BTO says they are best avoided, because they carry a higher risk of passing on disease. See should I still use a bird table?

Fledgling

A young bird that is fully feathered and has left the nest. The RSPB says a fledgling on the ground is usually best left alone if it is not sick or injured, because its parents are typically nearby. See I’ve found a baby bird on the ground.

G

Garden BirdWatch

A BTO survey in which participants record, each week, the birds and other wildlife in their garden, the food they provide and any signs of disease.

Garden Wildlife Health

A project that collects reports of sick and dead garden birds, amphibians, reptiles and hedgehogs. The BTO describes it as a partnership between ZSL, the BTO, Froglife and the RSPB. See what to do about a sick bird at the feeder.

General licence

A licence that GOV.UK describes as for “activities that carry a low risk to the conservation or welfare of a protected species”. In England they are issued by Natural England and Defra, and anyone relying on one must meet its conditions. See when can I clean out a nest box?

H

Hedgehog feeding station

A covered spot for hedgehog food that is hard for anything larger than a hedgehog to get into. Hedgehog Street suggests a length of piping or a shelter of bricks and paving slabs. See what can I feed hedgehogs?

Hedgehog highway

A gap between gardens that lets hedgehogs through. Hedgehog Street says a 13cm by 13cm square is enough for any hedgehog and too small for nearly all pets. See hedgehog highways and how big should a hedgehog hole be?

Hedgehog house

A shelter for a hedgehog to nest in. Hedgehog Street says site it in a shady, quiet area, use untreated wood, and keep food a couple of metres away. See where should I put a hedgehog house? and hedgehog house and feeding.

Hibernation

The winter sleep hedgehogs use to survive the cold months. Hedgehog Street says they usually hibernate from October or November to March or April, living off fat stored over the summer. See when do hedgehogs hibernate? and hedgehog hibernation and winter.

Hole-fronted nest box

A nest box with a small round entrance hole. The BTO says hole size decides which birds can use it, from 25mm for blue tits to 45mm for starlings. See what size hole does a nest box need? and the nest box guide.

M

Mealworms

An insect food for birds, sold live or dried. The RSPB says mealworms are fine to feed all year round, and that they should be eaten or cleared away by dusk the same day, especially if scattered on the ground. See bird food compared.

Metaldehyde

A pesticide used to control slugs on farms and in gardens. GOV.UK announced in September 2020 that its outdoor use would be banned, with use to end by 31 March 2022. See are slug pellets bad for hedgehogs?

Murmuration

The name for a large starling flock moving together at dusk. The RSPB says from November to February hundreds, and sometimes thousands, gather in coordinated aerial displays. See starling boxes and larger holes.

N

Nestling

A young bird that is not yet feathered. The RSPB says a nestling “should not be out of the nest” and will need help, ideally by being returned to its own nest. See I’ve found a baby bird on the ground.

Nyjer

A small seed offered in finch feeders, sometimes spelt niger. The RSPB names nyjer as one of the feeder foods goldfinches take. See nyjer feeders and goldfinches.

O

Open-fronted nest box

A nest box with a much larger opening than a hole-fronted box. The BTO lists robins, pied or white wagtails and spotted flycatchers as users. See sparrow terraces and open-front boxes.

R

Red List

The Red List of UK Birds of Conservation Concern. The RSPB says starlings and swifts are both on it; goldfinches are Green-listed. See common UK garden birds.

Rigid mesh feeder

A peanut feeder made of stiff steel mesh. The RSPB says nut feeders made of rigid steel mesh “are the only safe method of offering nuts to wild birds”. See peanuts and sunflower hearts.

S

Salmonellosis

A bird disease caused by Salmonella bacteria. The BTO says its signs are like those of colibacillosis: birds look weak, lethargic and fluffed up, and may have digestive problems. See cleaning bird feeders.

Schedule 1

A list of birds in the Wildlife and Countryside Act 1981 with extra protection. Section 1(5) makes it an offence to disturb a Schedule 1 bird while it is building a nest, or while it is in, on or near a nest with eggs or young. See can I remove a bird’s nest?

Seasonal feeding pause

The current RSPB and BTO advice to stop putting out seeds and peanuts from 1 May to 31 October, because the risk of spreading trichomonosis is higher then. Mealworms, fat and suet can continue in small amounts. See should I stop feeding birds in summer?

Subject access request

A request from a person for the recordings or information held about them. The ICO says that if your home camera records beyond your boundary, you must in most cases provide footage to someone it captured, usually within one calendar month. See can my bird camera film my neighbour’s garden?

Sunflower hearts

A sunflower seed food for feeders. The RSPB suggests a hanging feeder of sunflower hearts for finches, tits and sparrows, and names them as a food goldfinches take. As seed, they fall under the May-to-October pause. See peanuts and sunflower hearts.

Swift box

A nest box made for swifts. The RSPB says fix it at least 5 metres up, under the roof overhang, on a wall facing north, east or in between, out of direct sun. See where should I put a swift box? and swift boxes and house martins.

T

Teasel

A tall plant with spiky seed heads. The RSPB says goldfinches are fond of them, “inserting their beaks inside to extract the seeds”. See bird-friendly plants and berries.

Torpor

The state a hibernating hedgehog enters. Hedgehog Street describes hedgehogs lowering their body temperature to match their surroundings. See when do hedgehogs hibernate?

Trichomonosis

A disease caused by the parasite Trichomonas gallinae. The BTO lists difficulty swallowing, laboured breathing and swelling of the throat and neck as signs. The RSPB calls it highly contagious where birds gather, such as at feeders, and it is the reason for the seasonal feeding pause. See cleaning bird feeders and what to do about a sick bird at the feeder.

U

Usutu

A virus the BTO says was first detected in London in 2020 and is “potentially fatal to Blackbirds”. See sick and dead birds.

W

Wildlife and Countryside Act 1981

The Act whose section 1 protects wild birds, their nests and their eggs. In England and Wales, section 1 makes it an offence to intentionally take, damage or destroy the nest of any wild bird while it is in use or being built, or to take or destroy its eggs. See can I remove a bird’s nest? and the nest box guide.

Wildlife Incident Investigation Scheme

The scheme GOV.UK points to for suspected pesticide or rodenticide poisoning of wildlife, on 0800 321 600. See what to do with a dead bird in the garden and pesticides, slug pellets and wildlife.

Sources

All opened on 14 November 2026.