Protective Nests

Birds nest in trees, on the ground, on water, among cliffs, and in caves. They build their nurseries from plant materials, mud, dung, saliva, spider silk, pebbles, and animal hair. Some nests have roofs or multiple rooms. Some are simple scraped depressions in the earth or natural cavities in trees.

Most songbirds construct cup-shaped nests which require about 1000 trips to bring in building materials (1). The birds use their feet to scrape, chests to push, and beaks to manipulate twigs and grasses as they rotate. Exhausting! Why go to such an extreme effort? Predators. Birds living on predator-free islands nest on the ground.

Some ground-nesting birds have other ways of avoiding predators… like teaming up with defenders. The red-breasted goose of Siberia nests next to peregrine falcons. The geese act as look-outs for foxes; the falcons attack. Some birds build their nests in ant or termite colonies to protect the eggs.

These sleeping bird babies, pictured, are cardinals. Their parents built this camouflaged nest in the crook of a pear tree. If dad hadn’t stopped by with some breakfast, I would have never realized they were there.

1. Collias, N.E. 1964. The Evolution of Nests and Nest Building in Birds. American Zoologist. 4: 175-190.

Animal Dads

The animal kingdom has its share of great dads. In some species of birds and fish, males watch over a nest full of eggs and protect their young after hatching. Some insect- and frog-fathers carry offspring on their backs or in their mouths. But my award for best animal dad goes to seahorses (Hippocampus spp.). Male seahorses endure pregnancy and, after a few weeks of gestation, experience contractions when giving birth … to over 100 babies.

Currently, around 50 species of seahorses live in the world. They’re endangered though, due to over-collecting for the pet trade, souvenirs and traditional medicine.