How does a ladder trap work?
Similarly, how does a Larsen trap work?
The success of Larsen traps On the original design, the trap mechanism involves a spring door to each catching compartment which, when set, is held open by a split perch. To enter the trap, birds the size of a magpie or crow inevitably drop onto the perch.
Similarly, you may ask, why do farmers trap Magpies?
The cruel Larsen trap is used to catch magpies and other birds. Designed in Denmark in the 1950s, these traps are now banned there due to the suffering caused. They use a permanently trapped bird to lure in other birds. They fly down on to the trap, fall through a collapsing floor and find themselves trapped too.
Remember, crows are wild animals. In the US, it is illegal to keep native songbirds (crows included) as pets. If you want a pet you should get one, but if you're interested in crows, you'll have to learn to appreciate their charms from afar.