Author: David B. Williams

Following up my last post, I wanted to turn to bird houses made of stone. These were designed by Italian designer Raffaello Galiotto in cooperation with Arredo di Pietra. I learned about them from a nifty site, Stone-Ideas.com. Galiotto and his design team also produced houses for other beasts, including dogs.

The houses are made of travertine, one of the most commonly used building stones in the world. Because of the potential for diseases, each house has been treated with a protective coating. Known as the Redoxstone system, it is made of nano-particles of titanium dioxide or titanium (IV) oxide. According to the Stone-Ideas web site, ” This naturally occurring oxide of titanium can oxidize oxygen and organic materials directly giving it sterilizing, deodorizing and anti-fouling properties.” I imagine that this will make the birds happy.

[nggallery id=16]I do wonder how birds will take to these beautiful houses and whether the human owners would want birds dirtying these works of art. Please let me know if you order one and who visits it.

 

Humans are not the only species to build with stone. Several species of birds are well known for this trait. The desert lark (Ammomanes deserti), a ground nester found in the Middle East, builds low stone walls (about 4cm high) in front of its nest. One ornithologist described the stone structure as a “pebble glacis,” a type of defensive barrier found in medieval fortresses. In contrast, the rock wrens (Salpinctes obsoletus) of the American southwest appears to be more friendly. The birds live in labyrinthine world of crevices, nooks, passageways, and recesses and construct nests with stone driveways, one of which consisted of 728 flat pebbles ranging from ½ to 2 inches long.

[nggallery id=15]Early ornithologists hypothesized that this behavior might help the rock wrens recognize their nest cavity from the multitude of holes found in cliff faces or that the walkway kept “the young from falling into crevices or getting their feet caught in the same.” The pathways may take several years to build, though not by the same pair of birds. At this time, though, no one has come up with a conclusive reason for the paving.

Most impressive, though, is the black wheatear (Oenanthe leucura), known in Spain as pedrero, the stone quarrier or stonemason. During breeding season, a male will pick up an average of 277 stones and fly them back to the nest area. He deposits them in a pile, some of which contain up to four pounds of rock. The piles provide no benefit; the stones neither discourage predators, protect against weather, nor moderate temperatures. Instead, the females use the males’ stone toting facility to determine how much effort he will provide in raising their brood.

I can just imagine her thinking “Now, there is some good mating material. If he spends this much energy building a pile of rocks, imagine how devoted he will be to the kids.” Then again, I worry that she may be disappointed. He may just be a typical rock hound who likes to collect rocks.