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Iowa Public Television

  • Nature

Nature | A Crystal Chalice | PBS

Duration: 01:17
Program: Nature #2902
Broadcast Date: Nov. 2, 2011

Male swiftlets use their own building material, gluey saliva, to make their nests. Constructed layer by layer along the cave walls, it can be weeks of painstaking work.



Post Date: October 25, 2011