The Collaborative International Dictionary of English v.0.48:

Birdlime \Bird"lime`\, n. [Bird + lime viscous substance.]
   An extremely adhesive viscid substance, usually made of the
   middle bark of the holly, by boiling, fermenting, and
   cleansing it. When a twig is smeared with this substance it
   will hold small birds which may light upon it. Hence:
   Anything which insnares.
   [1913 Webster]

         Not birdlime or Idean pitch produce
         A more tenacious mass of clammy juice.   --Dryden.
   [1913 Webster]

   Note: Birdlime is also made from mistletoe, elder, etc.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Birdlime \Bird"lime`\, v. t.
   To smear with birdlime; to catch with birdlime; to insnare.
   [1913 Webster]

         When the heart is thus birdlimed, then it cleaves to
         everything it meets with.                --Coodwin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

birdlime
    n 1: a sticky adhesive that is smeared on small branches to
         capture small birds [syn: birdlime, lime]
    v 1: spread birdlime on branches to catch birds [syn:
         birdlime, lime]