The Latitude Variety Rule

By Dave Hanks
2/13/08

This rule states that areas near or on the equator will have a greater variety of species than areas closer to the poles. For instance, the Amazon Basin has so many species that many have not yet been classified. The northern countries do have fewer species, but there may be vast numbers within those species. The great caribou herds are an example.

Our place, west of Burley, is wildlife friendly and we have seen quite a few species on our property. We have documented 10 mammal and 107 bird species - which is a lot. However, if we lived in a southern state, there would be the opportunity to document many more.

If you have a desire is to see many types of lifeforms, plan a southerly trip. For this very reason, we have often traveled to the Rio Grande Valley of southern Texas. Texas has more bird species than any state in the union and its southern area has the most. A species that we especially enjoy, which is found only there in the USA, is the Great Kiskadee.

The Great Kiskadee is a large (9 ¾ inches) member of the Flycatcher family. We seek it out in the habitats it prefers - which are found along bodies of water where there are ample quantities of insects. They will also dive, kingfisher-like - but not totally submerge - for fish and crayfish. In fact, they remind me of a colorful kingfisher.

Their name results from a loud, slow, deliberate “Kis-ka-dee” call. Their nest is domed with one entrance and is usually in a thorn tree or thorny bush. Coral snakes are their main predator and thus the thorny nest site. They will also shun anything with that snake’s red and yellow color pattern. Kiskadees are monogamous, and the female will lay from two to five eggs.

We thrill to this birds gleaming yellow chest and belly, white head (with its black stripes), and the rusty under-wings and tail. It is always a highlight of a Texas photo excursion! We spent one whole morning chasing several Kiskadees around a cemetery but never got very close. But the next day at a private ranch I got lucky. They came in and sat in front of my blind – very close!

(The big, colorful Flycatcher on a stump in front of my blind)


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