Can i do audio monitoring with wireless headphones with a field recorder? I am new to audio. I was wondering if I can plug in a wireless headphone system, like a cheap bluetooth audio transmiter, to the audio-out jack of a field recorder such as Tascam DR-05 or Zoom H1 when used with a lavalier mic on the subject. 

I don´t need high quality sound monitoring just to make sure that the lavalier is turned on and recording. 

(I am planning on leaving the recorder and lapel mic for hours on a moving subject, "run &amp; gun" style, and I am afraid the subject will accidentaly unplug the cable, damage the mic or foul-up the recorder. I know there are wireless recorders but they are out of my price range, and I am working under the assumption that this way will yield better sound quality than a shotgun mic on camera. In case it´s relevant, my total audio budget is $200: either just a Rode Videomic Pro on camera or a Tascam DR-05+ ATR-3350 lav + cheap wireless headphones, buying either audio "solution" for now and adding the other later for more versatility)
I see no reason why not. You'd just have to make sure you find a transmitter that's battery powered, and small enough so you can bundle it with the micro-recorder. 

The question is; is it necessary. Would you be able to do anything, such as stop the event/filming, if there was a problem? Secondly; the feed you're monitoring is only going to tell you it's listening, not recording. 

We use the micro Tascams with Lav Mics for some events. My recomendation is:


Double Up:  Two Micro Tascam Units
Double Lav Mic Clip
Test Test Test your settings; input levels, auto gain vs manual, bit rate, etc, and get them both setup so you wont overmodulate. 
Run one slightly cold. Lower the gain / input on 1 mic by 5 db. So if the speaker gets really loud, you have a lower gain recording. 
Record in PCM 24 Bit if possible. You can then use compression in post to get super even audio. 
Use black gaff tape to tape OVER the hold button after starting the unit. This will prevent the units from having both a button pressed, as well as the guy turning off the hold button - it's happened to me. 
When you start the recorders in the field, at the very start; talk right into the mics, and say; DATE, TIME, EVENT, PERSON THE MIC IS GOING ON, ETC. 
Then tape HOLD and LAV them up. 


I'd do double mics over monitor, but not sure if that's what you want monitoring for.