To most of us, eggshells are the remnants of an English breakfast or something to paint on Easter morning. But to a small group of collectors, they are a dangerous and unlawful obsession. Why do they steal rare birds' eggs?
When police raided the home of Richard Pearson, they found one of the largest egg hauls ever recovered.
More than 7,000 eggs, including 653 belonging to the UK's most protected species such as a red-necked phalarope, were discovered in his Cleethorpes family home.
Officers also found 59 dead birds in a freezer in his garage and dozens of diaries detailing where and when he had found the eggs.
They seized equipment such as a rubber dinghy, waders, climbing spikes, syringes, cameras and sat-nav systems, all used to amass such a huge collection over a 20-year period. Pearson, 41, was sentenced to 23 weeks in prison.
Unusually, Pearson kept his haul at home
Birds take care where they lay their eggs - deliberately choosing tricky-to-reach spots such as crags, cliffs, marshes, trees and rooftops, to build their nests and protect their young from predators.
For Pearson and others like him, it's about the thrill of the chase - of outsmarting the birds, the wardens and the authorities, to track down that nest, to take the eggs, dispense with the living material inside, to proudly carry home the trophy and add it to the secret collection.
Mark Thomas, an investigations officer for the RSPB, says it's driven by compulsion, not greed.
"There's no real monetary value," he says. "It's a bit of a misconception that these eggs are worth thousands of pounds on the black market - that's not the case at all. It's a trophy."
The egg represents the memory of the daring expedition that produced it - up to Scotland, over moors, abseiling down cliffs to reach nests. And this mission is often well-documented, despite the risk of recording their crimes.
WHAT POLICE FOUND
7,130 wild bird eggs, 653 from highly protected species
59 dead birds in freezer in garage, 21 of which had been shot dead
Rubber dinghy, waders, climbing spikes, syringes, cameras and sat-nav systems
Data cards and diaries
Messages from Colin Watson, infamous egg collector who fell to his death stealing eggs in 2006
"In the Pearson case, classic example, he's got 15 years' worth of diaries telling us exactly where he's been, what species he's looked at," says Mr Thomas.
"He's then taken photographs of himself at the nest location, photographs of the nests, photographs of some of the birds, so it's all documented in his diaries".
Even though only a handful of people have been convicted for egg collecting, they have a lot in common.
"They tend to be aged between about 25 and 45, they're generally male - only men have ever been convicted," he says.
"They tend to come from a working class background - typically factory workers, roofers, builders and decorators, many have had multiple convictions. The same names come up year on year on year."
Stuck on cliffs
Tony, which is not his real name, is a self-confessed egger. He's been collecting eggs for more than 30 years and had his house raided several times.
"My introduction to bird nesting was as long back as I can remember," he tells BBC's Radio 5 Live. "My dad collected birds' eggs, his dad collected birds' eggs."
Growing up, there were at least three gangs of boys collecting eggs from the hedgerows, he says, and this nurtured his own craving to collect every bird's egg in the country.
"It's very challenging, it's not easy to do, it involves all sorts of tree climbing, cliff climbing, long walks.
"The desire to get there overrides everything, to the point where I got stuck several times. I've been stuck on cliffs for an hour at a time.
"I get excited by the oncoming spring because I just start to notice things. I notice when the birds start singing after being quiet all winter, I notice the first birds that start building nests."
Even at football matches, he says, he would hear a bird sing on top of the stand.
And although he concedes it's not cool or fashionable - in fact, it exposes you to ridicule - he maintains it's not damaging to the birds because they replace the eggs and build another nest.
"I don't feel any guilt as regards to cruelty to the birds, because it's almost a blood sport without the blood. It's a crime without consequences."
HOW THE LAW TIGHTENED
1954 Protection of Wild Birds' Act made it illegal to take birds' eggs from the wild
1981 Wildlife and Countryside Act made it illegal to possess or sell any UK wild bird's egg
2000 Countryside and Rights of Way Act introduced custodial sentences for these offences
Many collectors rent lock-up garages or storage spaces, and specimens have been found stored in attics, basements, under floorboards, and even hidden in wall cavities. Some collectors bury hoards near nesting sites.
Pearson had not attracted attention, so was confident enough to keep his eggs in his house with his family, which made the job of the RSPB easier.
His collection included eggs from choughs, peregrine falcons, barn owls, golden eagles, ospreys, and nearly 40 black-necked-grebe's eggs. The RSPB estimates there are only between 40 and 60 breeding pairs of black-necked grebes in the UK.
It says Pearson's actions stopped these birds from breeding and for the golden eagle, each clutch represents their only offspring for that year.
A dead honey buzzard was found at Pearson's home
Egg collectors like Pearson are usually tracked down using a sophisticated network of inside information, from collectors, partners, friends, bird watchers or wardens.
His collection will probably go to a natural history museum and Mr Thomas hopes this discovery will be one of the last of its size, because as the law strengthened, more collectors have been jailed.
"So whereas 10 years ago we might have two to three hundred reports per bird breeding season of egg collector activity, now that's right down to maybe 50 reports in a typical year."
But he worries that some of the hard-core collectors are simply going abroad to target very rare birds such as the Spanish imperial eagle.
Below is a selection of your comments.
Very interesting story. More so than usual, as the information received by way of diaries etc could be very important to the RSPB in looking at facts figures and trends over the years. Great work in tracking him down. Even though he has done untold damage over the years, I'm sure he probably has a love of birds, as a good deal of birders are ex egg-collectors as well (although not usually to this scale I'm glad to say). He could be very helpful to the RSPB, and I think he should be encouraged to try and mend his ways not only by the sentence given, but by working alongside the RSPB in order for them to learn from each other.
I think it's unfair to steal a bird's egg. How would you feel if someone stole the embryo of a future child straight from your womb? Also this is a terrible crime, adding to the risk of extinction to many rare birds. He should be ashamed.
Emma Halton, Plymouth, England
It's amazing that our society can track down and imprison someone for a minor infringement, whilst allowing terrorists and other criminals to walk our streets. How many people feel any safer now this person is behind bars?
David Smith, Scunthorpe
The man's an obsessive nut. To declare that what he's doing is 'not damaging to the birds' shows his complete lack of appreciation of the consequences of his actions. Even if the birds do return to the nest and do lay another egg - he has nevertheless destroyed the chick in the egg he's taken. That fact is inescapable. Further to that he boasts that his father and grandfather have been doing the same for years. The man should hang his head in shame for all the wanton destruction to embryonic wildlife he's caused. It's a huge pity he's not focussed his considerable 'sleuthing' talents in a more worthwhile direction.
Susie Q, Cheshire
Could not these people, whenever in the year they are arrested, be sent to prison from say, mid-February to mid-June, so that the breeding birds are protected when they are at their most vulnerable? When given, for example, a 12-month sentence the thieves could be made to serve their time in three instalments over a three-year period.
Mick Marchant, Tenterden UK