Falco and Carlo get excited when they find what they're after. It might be a rotting eagle corpse, a chunk of poisoned meat, or eggs smeared with deadly toxins. The pair make up a canine wildlife crime detection unit and they hand their grizzly finds over to Hungarian conservationists. Lately, they've been busy.

Read more: Miniature sleuths to sniff out transnational wildlife crooks

Lockdown has been a boon for some wildlife, with animals like deer and lynx appearing in usually bustling cities. However, conservationists say with fewer potential witnesses around, there has also been a rise in the illegal shooting, trapping, and poisoning of animals. 

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"Wildlife crime" typically evokes images of pangolins sold in China or rhinos poached in Africa. But it's a problem in Europe too. 

Raptors at risk

In the European Union, all birds of prey are protected ; aside from a few special exemptions, it is illegal to kill these birds or disturb their nests. Yet humans remain a threat to their survival.

Read more: Protecting South African wildlife from poaching during the coronavirus pandemic

"Studies show that there should be about 300 hen harrier pairs in England, but there are only about 10 to 15. The reason for that is illegal persecution," Mark Thomas, head of investigations at the UK's Royal Society for the Protection of Birds, told DW.

Many convictions for raptor persecution have been linked to the shooting industry. Birds of prey may be targeted for their perceived threat to game species such as pheasants, grouse and hares that are hunted for food or sport — or to livestock, or even pigeon fanciers' prize birds. Egg collectors looking to add to their treasure troves are also a threat. 

Thomas says that since lockdown began, reports of possible persecution jumped from a few per week to an equivalent number each day. His team has been busier than at any time in more than 20 years. 

Enlisting dogs to protect eagles 

Illegal killings of raptors in Hungary and Slovakia have also spiked.

Birdlife Hungary reported 77 animals — including white-tailed and eastern imperial eagles — found poisoned between January and April this year. That's more than double the average for the past four years. 

"It's hard to tell why there is an increase, but it might be that people think the police are too busy to deal with wildlife crime right now," Birdlife Hungary's Márton Árvay told DW. 

Bird conservation organizations in mainland Europe increasingly use dogs to fight wildlife crime. The canine investigators sniff out carcasses and banned toxins like carbofuran, helping to bring prosecutions against poachers.

Read more: King of the skies: The return of the eagle

According to Raptor Protection of Slovakia , shooting and poisoning had fallen dramatically since the Slovakian police began using sniffer dogs to enforce conservation. Yet the organization has reported a rise in raptor killings during lockdown. 

Working with hunters 

In the UK, this wildlife crimewave is likely to fuel a long-standing debate over raptor killings. 

Many conservationists want to see increased fines and prison sentences for raptor persecution. And some are calling for mandatory licensing for shooting estates — where hunters are provided with specially bred game — or even a complete ban on some forms of shooting. 

Organizations representing shooting estates say they are being unfairly scapegoated. The UK's Moorland Association told DW it has a zero-tolerance policy on raptor persecution and that land management of shooting estates helps many rare birds. 

In Hungary, Árvay says until this year, raptor persecution was diminishing, in part due to the EU Helicon  and PannonEagle conservation projects, which actively engage with hunters to raise awareness of these birds' importance and research raptor-friendly ways to protect game. 

Árvay says many hunters were concerned as eagle populations slowly grew, but that is changing.

"We have been working closely with hunting associations to increase habitat for game species, ensuring there is plenty of game and thus reducing conflict with raptors," he said. "Most hunters now have a good perception of birds of prey." 

Árvay and his team hope this relationship will continue to develop after lockdown.

Read more: German city issues coronavirus pigeon-feeding permits

Illegal caviar

It's not just birds that have been targeted in recent months. Romania, Bulgaria, and Ukraine have seen a surge in illegal fishing. 

Sturgeon have been around since dinosaurs walked the Earth but are now among its most critically endangered animals. Sturgeon caviar from the Danube used to be legally sold across Europe, but dam construction and overfishing caused populations to collapse to just 1% of previous numbers. 

All sturgeon species are now protected. But Jutta Jahrl, WWF project manager for the EU Life project on Danube sturgeon says there has been a rise in poaching of the fish under lockdown. 

Read more: Poaching, dams imperil ancient Danube fish

"Unfortunately, owing to Covid-19 many people in the area are losing their jobs, and may turn to sturgeon fishing from desperation," Jahrl told DW. "Sturgeon caviar commands a high price as a luxury good."

As tourism and other industries ground to halt due to Covid-19, there remained no shortage of customers seeking to buy caviar on the black market.

Jahrl's team is working to keep these ancient creatures swimming into the future by restocking the Danube with baby fish. 

Meanwhile, the fate of raptors like the eastern imperial eagle lies, to some extent, in the paws of dogs like Falco and Carlo, bounding across Hungary's great plains eager to uncover fresh crime scenes. Their handlers, however, hope their future searches will be less fruitful than over recent months.