The "bird-dog" agreement that my investor and I used last summer was just a portion of a larger agreement between the two of us written up for our specific situation. So I do not have my own bird-dog/referral/assistant agreement to post. But here are a couple I found by googling. PLEASE remember to have them reviewed by an attorney and tweaked to what is legal for your state. I would be most comfortable with the one that states a flat fee for "assistant" services as this cannot be mistaken for a "real estate agent's" percentage.
Also, you may want to use one for each property you find, or keep a list of each property you present to each of your investors.
If there has already been something similar posted in the forums I couldn't find it (nor do I remember seeing one). I know there's a lot of good info, but wasn't sure if there was a contract posted. If so, you could leave a link here.
Finder’s Fee Agreement
Date:_____________________ at__________________________, (Enter State)
In consideration of services to be rendered by ____________________ (Finder), and _______________________________________________(Client) hereby employs Finder to refer to Client a prospective:
Single Family Home,  Rental Units, Land , Commercial,
buyer owner, borrower tenant Other___________
1. Finder agrees not to participate in or conduct any negotiations with propects, or solicit loans on behalf of prospects. Finder is/is not licensed by the (Enter State) Department of Real Estate.
2. Finder hereby delivers to Client the name and identity of the following prospect:
Single Family Home ,Rental Units, Land , Commercial
, buyer owner , borrower tenant , Other___________
3. Finder hereby delivers to Client particulars concerning a real estate parcel that Client might want:
Legal Description: _________________________________________________
1. As compensation for Finder’s referral, Client agrees to pay Finder as follows:
[ $ ___________
 _____________% of the net profit upon sale.
 _____________% of the net equity upon purchase.
 Other:___________________________________ ___________________
1. Finder’s compensation is payable as follows:
 Upon the closing and sale of the transaction involving the above-cited real property (#3), or upon the closing of the first transaction involving the above-cited prospect (#2).
 Other: ________________________________________________________
2. Should the prospect or the property not result in a transaction involving Client within ______months of the date of this agreement, Client shall owe Finder no compensation.
3. Additional terms and conditions: __________________________________________________________
Understood and Agreed:
Finder:____________________________________ Date ________________
Client:_____________________________________ Date ________________
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