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Saturday, May 12, 2012

Chimney Swifts need homes!

Chimney Swift
Chimney Swifts nest (duh!) in chimneys. The kind that have  insides made of brick, rock or something else they can grab onto.

Before this continent was settled, however, they nested in hollow trees, which were everywhere.  Trees such as  sweetgum,  sycamore and basswood especially, since these trees, when they die naturally, die from the inside out, and naturally hollow out.

These days trees are chain-sawed down, and most homes have their chimneys capped. Many chimneys are made of sheet metal on the inside. (Chimney Swifts can't get a grip)  As a result, the species is declining; a shame because it's one of the most aerobatic fliers around!

Some people have built artificial chimneys to attract them (see pic); both for their in-flight beauty and their insect-decimating appetite.
artificial chimney

My what big eyes you have!  Birds have huge eyes in comparison to their heads. Far more than humans! The relatively large pupils let them see in much lower light than humans. That's a big reason why birds are especially active in low light (like dusk and dawn).  Owls, Nighthawks, Swifts, Cardinals and Whipoorwills have the largest eyes of birds in north Texas, and can see in the least light.

Wednesday, May 9, 2012

Did climate change bring them here?

Tropical Mockingbird
The appropriately-named Tropical Mockingbird is a close cousin of the typical Mockingbird (technically the Northern Mockingbird) that's common in north Texas.

This Tropical Mockingbird was recently spotted in the southern part of Texas.  Others have recently been spotted too. That's curious because this is the first sighting of the tropical species in Texas ever. It's normally abundant in northern South America and southern Central America.

Like many of you, we try to garden organically. So we use a safe, low-cost herbicide to kill weeds - vinegar. It doesn't kill or sicken every living thing (including birds) in your yard, and you can buy the ingredients cheaply at almost any grocery store.

I'm certainly no botanist, so I have no idea why it works. But here's how I make it;  take one gallon of 10% vinegar (undiluted, from grain alcohol), blended with 1 ounce of citrus oil and one tablespoon of either molasses or plain liquid soap. I just put it in an old spray bottle without adding water, and spray it directly onto unwanted vegetation. (It may need 2 or 3  applications if the plant is particularly deep-rooted)

A word of caution; it works best on actively growing vegetation, so don't  expect good results during our superheated weather of July and August, when many plants go into dormancy.

Pileated Woodpecker:

Sunday, May 6, 2012

The harsh challenge of crossing open water

Migrating birds often have to cross large expanses of open water with no place to stop and rest. No place to re-supply food either. Most Hummingbirds do this twice a year (although some fly along the coast). Some die trying to cross the Gulf, and the ones that make it are much skinnier and are starving when they arrive.

Purple Martin
Purple Martin is another north Texas species that crosses the Gulf during migration. They need to fly non-stop for 72 hours, travelling around 660 miles a day. That's equivalent to a human running at a 4-minute-mile pace for 80 hours straight.

American Robin
Robins are eating machines. Researchers estimate that each brood of  nestling American Robins eats about 3.2 pounds of food. Since they're "insectivores" that means eating only insects (and worms). While in the nest (an average of 13 days) each one grows from 5.5 grams to 56 grams - over 1000 percent! On its last day in the nest, a nestling may eat 14 feet of worms, or whatever else the territory produces.