According to the pilot of an Ercoupe 415-C, while on climb out at approximately 1,300 feet, he noticed wood pieces and feathers coming into the cockpit through the open canopy, and "an extreme vibration ensued throughout the airplane." The pilot shut down the engine, and performed an emergency landing in a pasture. The airplane subsequently impacted a shallow ditch that was obscured by tall grass. The nose gear collapsed, the right wing spar bent aft, and the firewall buckled. The airplane was equipped with a two blade Sensenich wooden propeller; after the accident the pilot reported that "one blade was splintered." The pilot reported no mechanical malfunctions prior to the event, which was determined to be a bird strike.