Taking a cue from PaleMale dot com, I am posting Mayor Bloomberg's contact info below should you wish to address the rodenticide issue with him directly (taking it to the top, as it were).
Per PaleMale dot com, some contact email addresses and phone numbers of places that had been listed on his site for folks to contact regarding their use of rodenticide near Hawks' domains are reportedly no longer working or accepting contact.
If there are other authorities you prefer to contact, then by all means, do. Any form of contact with anyone who may listen and invoke policy change is worthwhile.
But should you wish to contact Bloomberg himself, the below should be helpful:
Mayor Bloomberg's Online Contact form:
The Online Contact Form accepts a maximum of 300 words so a longer letter would be best mailed via hard copy.
Mayor Michael R. Bloomberg
New York, NY 10007