Trombeta is the brand name for a solenoid that connects the house battery to the chassis battery when the engine is running.
BIRD stands for "Bi-Directional Isolator Relay Delay" which allows either the House system (converter) to charge the chassis battery or the engine generator to charge the house battery depending on which circuit has the higher voltage.
Google "rv bird relay" for more info.
Edit: Older RVs used a Trombeta while newer RVs use a BIRD. Mine has a Trombeta that lasted about a year before failing. I replaced it with a similar solenoid, not a Trombeta, from eBay which has lasted for about 10 years without a problem.