Matthew Stabler, 24, of Salters Lane, Durham and Paul Prosperini, 39, of Bewick Park, Wallsend, pleaded not guilty to the offence.
However, following a one-day trial, they were found guilty by magistrates.
Both men have been convicted and handed a combined total fine of £1,477, including victim surcharges and costs.
The two men were detained on suspicion of the offence on land between Lowthorpe and Nafferton on Sunday, November 14.
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They were arrested following a co-ordinated response by the Farmwatch community and officers from the Driffield Community Team and Rural Task Force.
Rural Task Force officer Kevin Jones said: “This has been a fantastic result thanks to some really proactive teamwork between the local Farmwatch, community, and our teams.
“This result sends a very clear message to those who are thinking about coming into the East Riding of Yorkshire to commit wildlife crime.
“We will take action on every occasion, and will look at utilising all the available legislation to prevent, deter and prosecute those who decide to engage in criminality around our countryside.
“Wherever we have the evidence we will prosecute offenders and we welcome the help of our rural communities in letting us know of incidents in their area.
“If people see anything suspicious, they should always call 999 for suspected crimes in progress or 101 for non emergency incidents.”