Wednesday, October 2, 2013

The only two reasons why birds sing


Harris' Sparrow
The only two reasons a bird sings are (1) defining and protecting its territory, and (2) attracting a mate.  It’s not meant to disturb your sleep or to complain that a feeder’s empty, though those may be secondary consequences. A singing bird doesn’t really care how a song affects us. He just cares if his message gets through to other birds.

Singing is almost always directed at members of the bird’s own species. Each species has a different song (or songs), and individual birds of the same species sound pretty much alike. However, there is often a slight variation among different populations of the same species; for instance a wren in New England probably sounds strange to a wren from Louisiana. Also, almost all birds have two “voice boxes”, so they can sing intricate and complex songs that you and I can’t possibly imitate.

Typically only the male bird sings, although the female of some species can also sing. The reason is common sense; the males want to draw attention to themselves, whereas females want to remain hidden, since they are often in the vulnerable position of incubating eggs or caring for young.

Most bird songs establish territory. Within this territory a pair of birds will get the bulk of their food, hunt for nest material, raise their young, and so on - so a territory must be aggressively guarded from rivals. The relative size of a territory varies greatly. It depends on the amount of food, shelter and nesting material it contains.

To establish a territory, the male chooses a series of song posts from which to sing (specific trees, fence posts and such).  The borders are invisible, of course, but if a rival male crosses into an occupied territory he will be instantly challenged. When a male challenges, the ensuing fights or chases may involve aggressive bursts of song meant to scare the intruder. The territory’s original “owner” almost always emerges as the winner.

Special attractions that appeal to all birds, like feeders and birdbaths, seem to be excluded from the exclusive territory of just one bird. They’re out-of-bounds or “neutral territory” which all birds can visit with only minimal annoyances from other birds.

A bird’s song means nothing to birds of a different species. The other bird probably has different food and nesting requirements, so different species often live in the same area, ignoring the songs of other species. Within a given territory it’s possible to have a Robin, a Cardinal, a Chickadee, a Mockingbird and Bluebird, all nesting without interfering with each other’s needs. One species eats seeds, another eats insects and so on…each exploiting its own environmental niche. An example is the Brown Creeper, who inspects tree bark for insects while going UP a tree. The Nuthatch does it while going DOWN a tree. So they can both live on the same tree, and not infringe on the other’s environmental niche.

A bird’s song can advertise to a female that an unattached male is present, offering the female a mate and a home. He’s announcing his status and virility (some call this the “shiny sports car” syndrome).  The female is thought to be able to distinguish between the songs of a bachelor bird and one that is paired. 

Some birds also have a sub-song.  It’s usually a quieter and lower version of their normal song. It doesn’t carry very far and is usually only heard in fall and spring. Some sub-songs are almost certainly sung by young birds, so it could be thought of as  ”practicing”.

Bird calls are different from songs. They are quite short, simple sounds and so have only one or two syllables; sort of like a sound you or I might make if startled, punched in the stomach or attacked by a bear. Calls communicate totally different messages from songs – such as signaling that a predator is very near, showing aggression, showing surprise or calling young birds home.

Whatever song a bird makes, it typically sounds pleasant and sweet to us. But to the intended audience, other birds, it may mean ”get out of MY territory” or “I can help raise healthy nestlings” or “watch out for that hawk up there”.

 

OWEN YOST, in addition to being a blogger, is a licensed Landscape Architect emeritus who has lived and worked in north Texas for over 30 years. He is a member of the American Society of Landscape Architects (ASLA), International Federation of Landscape Architects, National Wildlife Federation and the Audubon Society. His office is at Yost87@charter.net in Denton.

 

Sunday, September 29, 2013

Sidestep spoiled birdseed when you ground-feed

Black-crested Titmouse
 Ground-feeding of birds is wonderful, mainly because it's so natural. Most of the bird species that come to feeders take most of their natural nourishment from what’s on the ground anyway.  However, moisture (usually in the form of rain) will rapidly spoil seed that’s scattered on the ground.

Spoiled seed can lead to sick birds. Go ahead and scatter seed on the ground for birds whose natural food supply is covered up, however.  Squirrels will probably find the leftovers.  But don’t let seeds (I’m not talking about the husks) stay on the wet ground for more than 2 or 3 days.

Rose-breasted Grosbeak
Blue Jay
At our house, we have a ” tray” or “platform” feeder, with a screened bottom. It’s hung several feet off the ground. Rain simply goes out the bottom, and the wet seed dries out quickly.


 We "run" about ten feeders (It varies with the seasons). You'd think that the cost of seed would monetarily drain us. No!  For one thing we use safflower in a few feeders that squirrels can reach. That's because squirrels hate the taste of safflower and leave those feeders alone. We also have a couple of "Squirrel-Buster" feeders that are designed to totally exclude squirrels (no squirrel has gotten a single seed out of a "Squirrel-Buster" in the 18 years we've lived in our house).
 We fill feeders when we want to, not when they're almost empty. If a full feeder is your goal, fill it with old nuts and bolts  (that's sarcasm). Besides, wild birds get far less than a quarter of their food from feeders anyway.
We strongly advise against buying birdseed from a grocery store or big-box store, whose main interest is low unit cost. Yes - the price per bag is lower, because it's largely made up of cheap seeds that birds in north Texas won't eat (like milo, corn etc.).  It seems like it would last longer for the same reason, but that's not so. It actually winds up costing you more because what actually happens is that a bird will pick up a junk seed like milo, realize he doesn't want it, and drop it to the ground.  Creatures like rats and mice will pick up these junk seeds; it soon attracts their friends. Result: your feeder gets emptied about as fast as before, you need to buy more seed sooner, and you have a rodent problem.

 

OWEN YOST, in addition to being a blogger, is a licensed Landscape Architect emeritus who has lived and worked in north Texas for over 30 years. He is a member of the American Society of Landscape Architects (ASLA), International Federation of Landscape Architects, National Wildlife Federation and the Audubon Society. His office is at Yost87@charter.net in Denton.

Wednesday, September 25, 2013

This area is called "the Cross Timbers" Why??

 Most of this north Texas area is called “Cross Timbers”. It seems that many people think that the term “Cross Timbers” is merely a made-up name. Wrong!

Actually, Denton is mostly in the Eastern Cross Timbers –the popular name for this area in “pioneer-speak”. Unfortunately, there is hardly any real “Cross Timbers” left today, having been plowed under and paved over to accommodate subdivisions, shopping malls, highways and the like. 

The origin of the phrase can be traced down several paths, depending on who’s talking. The most popular, however, has its roots in the natural geography and vegetation of this area. Most forests here run in north-south bands.  Rivers, on the other hand, run roughly east-west. The result was that pioneers (who fervently avoided dangerous river crossings) had to cross bands of north-south forest as they traveled between the rivers, heading generally west. Thus the name:  ”Cross Timbers”.

In academic, ecological terms, this area was a “savannah” which is defined as a grassland prairie spotted with trees. (Mostly post oaks and blackjack oaks in this instance). In many areas the characteristic trees were so thick that they became forests. In the 18th and 19th centuries, the Cross Timbers was a well-known geographic feature marking the eastern edge of the American grasslands.

Nowadays, however, there are embarrassingly few remnants of the Cross Timbers left. Much of the original soil has been “urbanized” by extensive construction, farming and introduction of non-natural soil. Even though 19th-century naturalists generally put the range of the Cross Timbers region over a large stretch of Texas, Oklahoma and Kansas – the original ecosystem is now found in only a few large parks, preserves and isolated patches of countryside and floodplains.

Many kinds of plants thrived in the Cross Timbers, but almost all the natural canopy trees were post oaks and blackjack oaks. Amongst them were millions of tough smilax vines (those pesky, thorny vines also called catclaw vine or greenbrier). The combination was almost impenetrable, causing the 19th century author and statesman, Washington Irving, to call the Cross Timbers “forests of cast iron”.
Washington Irving
But vegetation would not exist at all in this type of soil, if compaction and “traffic” were not limited in some way. The Cross Timbers soil is sandy, porous, unstable and nutrient-poor. Consequently, the natural vegetation is fragile and easily killed.

The Cross Timbers is tied to the sandstone geology, and is limited by the local climate; rainfall being the biggest factor. The area (which encompasses Denton) gets between 23 inches and 43 inches per year. Coupled with high summer temperatures and frequent droughts, this area is ideal for the native oaks. When artificial irrigation is introduced, many other plants will survive here, although vegetative life is still very fragile.Under sprinkler systems, much of the native vegetation may suffer from overwatering.

Despite a growing awareness of the Cross Timbers’ ecological and historic importance, what little remains is being demolished at an alarming rate.  In the words of author Richard Francaviglia  “…developers are often either ignorant or arrogant. Thus, the Cross Timbers yields to the bulldozer in many locales, especially in the suburban areas where the prime real-estate sites...entice developers.” (Dr. Francaviglia authored ‘The Cross Timbers’ and ‘A Natural and Cultural History of the North American Cross Timbers’).

Dr. Francaviglia also noted that in some areas some land developers are preserving remnants of the Cross Timbers as they carefully develop sites. Also, the opportunities for tourism revenue are huge. “Few regions present better opportunities to integrate heritage tourism with conservation than the Cross Timbers.  Descriptions of this region’s forest abound in the historic literature and the Cross Timbers was often THE most prominent feature on historic maps of the period 1830 – 1880.” 

So, as you look around a remnant of the Cross Timbers, glimpse an Eastern Bluebird perched on a limb, see a Red-tailed Hawk soar, hear a hidden Warbler or Chickadee, and photograph a mass of Bluestem grass, think of all that came before us, and imagine all that the Cross Timbers used to be.



 
OWEN YOST, in addition to being a blogger, is a licensed Landscape Architect emeritus who has lived and worked in north Texas for over 30 years. He is a member of the American Society of Landscape Architects (ASLA), International Federation of Landscape Architects, National Wildlife Federation and the Audubon Society. His office is at Yost87@charter.net in Denton.


 

 

 

 

 

Sunday, September 22, 2013

avian mimic


Northern Mockingbird
A few species of birds are the only living creatures, other than humans, that can imitate sounds that they weren’t born to produce. This ability to learn and imitate strange sounds is called verbal mimicry, and the species of birds that can do it are called mimics. The most notable Texas bird that can do it happens to be our state bird:  the Mockingbird. I've heard of them (technically, Northern Mockingbirds) mimicking phone ringing, computer "dings" and backing up "beeps" of trucks.




Starlings actually belong elsewhere   

Like Kudzu vine and Dutch Elm disease, starlings (technically, European Starlings) didn’t occur naturally in this hemisphere at first. An
Starling (in fall)


Starling

eccentric Shakespeare enthusiast released about 100 starlings in New York in the 1890s. Before that time they only existed in Europe. He thought it a clever idea to bring to the “New World” every species mentioned in Shakespeare’s writings, with no thought about natural prey, habitats, native-ness etc. Now we have over 200 million of them, and fewer native species.  Alas!
 

OWEN YOST, in addition to being a blogger, is a licensed Landscape Architect emeritus who has lived and worked in north Texas for over 30 years. He is a member of the American Society of Landscape Architects (ASLA), International Federation of Landscape Architects, National Wildlife Federation and the Audubon Society. His office is at Yost87@charter.net in Denton.

Wednesday, September 18, 2013

Do you harm migrating birds by feeding them?


 
Eastern Phoebe
    About now, some folks put birdfeeders, birdbaths and such away until spring. They've bought into the myth that all the birds leave here just before cool weather, and feeding them interferes with their natural migrations.  That’s simply not so!  Many birds (Chickadees, Cardinals, Woodpeckers, even Robins etc.) stay in the north Texas area all year. Some birds (Martins, most Hummingbirds, Swallows etc.) fly to even warmer climates. Many others migrate TO climates like ours for the winter. The result is that there are at least as many birds here during the winter as there are in the summer. Probably more!
The old myth that feeding birds right before cool weather somehow makes them stay here, just won’t go away. The truth is that the food in your feeders has absolutely nothing whatsoever to do with birds’ natural migration schedules. Migration times are governed by day length, sun angles, air temperatures, winds and the bird’s heredity. Migrating birds, often embarking on a flight of hundreds and hundreds of miles (or pausing along the way) will often seek out a “feedered” yard so they can stoke up for the trip. Many uncommon birds are sighted this way.

Still others believe that feeding birds makes them “lazy” and dependant on us. The scientific truth is that wild birds get only about 10 to 20 percent of their total diet from feeders. The vast majority of their food is still berries, seed, insects and other naturally-found stuff. The food in backyard feeders is only an occasional convenience or a snack. In an icestorm or snowstorm, however, a feeder can literally be a lifesaver. And it's also an “instructional tool” for young birds and their parents.

Scissor-tailed Flycatcher
Actually, the period after (roughly) mid-October is when the wild birds probably need our help the most. The natural food is harder and harder to find, but the birds still need to eat every day just to stay alive. They still need to take baths to get clean, too.

What do the experts do? Noted ornithologists Donald & Lillian Stokes say, “birds always need your help. The best time to start feeding them is now…and never stop.” I can’t rank myself among the “experts”, but I feed birds via my 10 (or so) birdfeeders every month of the year - mainly because I enjoy watching them every month of the year. I leave my birdbaths out too, knowing that birds need to fluff up clean feathers to stay warm. (Sure,  the water freezes sometimes but the birds deserve our extra effort.) I also plan to put out nectar for the dark-orange Rufous Hummingbird, which will winter here.

The year-round feeding of wild birds in Texas has contributed to our being able to see several species that used to avoid Texas, such as Towhees, several Warbler species, Nuthatches, Orioles and Vireos. They’re spotted as they rest up along their migration routes. This is perfectly natural “range expansion” that has occurred here over the last 30 years. (Some say that they were here naturally decades ago, but were driven away by their natural feeding areas being turned into shopping centers and subdivisions. So we’re just making amends by feeding them!)

In a recent publication from Cornell University Laboratory of Ornithology, the author pointed out that “in winter… the berry-laden vegetation has mostly withered or been consumed, and most insects have died or become dormant. Finding food can be especially challenging during cold weather.”  While the winters in north Texas may not be as cold and snowy as most, our birds are certainly impacted by the fact that natural foods and protective shelter are gone.

Whenever you feed the birds, it’s very important to keep feeders clean, preventing the possibility of diseases. Feeders should be cleaned at least twice a year by soaking them in a solution of water and vinegar (or bleach) and thoroughly drying them. Your birds will thank you, and even moreso when you take care of them through a Texas winter.

 



OWEN YOST, in addition to being a blogger, is a licensed Landscape Architect emeritus who has lived and worked in north Texas for over 30 years. He is a member of the American Society of Landscape Architects (ASLA), International Federation of Landscape Architects, National Wildlife Federation and the Audubon Society. His office is at Yost87@charter.net in Denton.

Sunday, September 15, 2013

Texas birds are everywhere!!

This is a really nice video about The Big Day in Texas; when a group from Cornell attempts to break the record for the most kinds of birds seen in one day. You may recognize some of the places and/or help you plan your next vacation. If you're vacation is this winter, remember that there are more birds here in the cooler months than in the summer. Texas is a southern state after all!

 

 

 

Enough flowers in your yard?     On average, a Hummingbird visits from 1000 to 3000 flowers per day, in pursuit of nectar. If the "target" flowers aren't in your own yard, they'll just go to the neighbors'.

 

All flowers produce nectar; it's what attracts pollinators. But some types make a lot more than others. For a good average, I suggest 5 to 1. That is, 5 parts of clear water, blended with 1 part of dissolved table sugar.

 
Right now, Hummingbird migration is underway. There are fewer in Texas every day, but the remaining ones are eating voraciously - bulking up for the flight to Central America. By the end of the month they're normally all gone. But we leave nectar feeders up for a few weeks more, to feed Hummers migrating from up north.



OWEN YOST, in addition to being a blogger, is a licensed Landscape Architect emeritus who has lived and worked in north Texas for over 30 years. He is a member of the American Society of Landscape Architects (ASLA), International Federation of Landscape Architects, National Wildlife Federation and the Audubon Society. His office is at Yost87@charter.net in Denton.

Wednesday, September 11, 2013

hurricanes and their affect on birds


Major storms such as hurricanes are undeniably harmful, and have been occurring for ages – and will certainly occur again. Since we're in the middle of hurricane season, let's learn about birds and migration during a hurricane, while leaving news of the impact on humankind to those who know better than I.

As you might imagine, many birds fly rapidly from the area as a hurricane approaches. They’re alerted by the sudden drop in barometric pressure which they instinctively know means “leave fast” – after all, their species has been dealing with storms for ages. However, some will choose to stay put if they can find shelter, and ride it out.

In addition to the drastic pressure change, hurricanes generally approach from the south. They’re huge storms, with counterclockwise winds, carrying lots of water. This means that ahead of the core of the storm, winds will be blowing essentially from east to west inland from the upper gulf coast.  (The same principles apply when a hurricane approaches any other land mass).

At the same time, our fall-migrating birds are heading from north to south, many flying down the Central Flyway (centered on the Mississippi River), and will be driven west toward Texas ahead of the hurricane's landfall. This will obviously increase the number of migrating birds coming through Texas, and decrease the number significantly that are moving through places to the east of the storm. As the storm approaches and makes landfall, winds will be strong, and birds would probably not brave headwinds in excess of 100mph just to get to the gulf coast. The beaches in Texas are better anyway!

The east side of the storm, with winds out of the south, is the "dirty" side of the storm, as these winds carry more wet debris and are far more destructive than east-to-west winds. So, for example, east Texas should be spared from much wind damage by a hurricane that hits Louisiana. A hurricane loses strength over land also. These counterclockwise winds discourage birds from flying into the nasty east side of incoming storms.

The non-migrating birds in the path of a hurricane just hunker down in a hole in a tree, under the eave of a house or in the center of a large tree. Some, unfortunately, will be killed. Others may get blown far away by a big storm (Katrina blew many birds as far away as Tennessee).
Where am I??

While watching migrating birds may be good in Texas and slow in Florida during a hurricane hitting Louisiana, another group of birds may visit. These are the water/shore birds (“pelagic” species) that live along coastlines. Many of them get "trapped" in the relatively calm eye of the hurricane and carried well inland, to places and habitats they haven't a clue about. Naturally, they turn around and head back to the coast as soon as they can. But it’s not out of the question that someone will see, for instance, a Shearwater or Avocet in north Texas as the remnants of a hurricane pass through. Birds trapped in the eye of an active storm have very little natural food around, since the preceding east-west winds scoured the area via high winds. Pelagic birds normally drop from what’s remaining of the hurricane’s “eye”, into large lakes. (Many pelicans were spotted in and over Lake Lewisville during hurricanes Katrina and Ike).

Of course, the biggest threat to all kinds of birds is the loss of their habitat and natural food. A Cardinal who lived in a Mississippi forest, for example, may have his forest blown down. Or a Meadowlark may suddenly have his meadow underwater. Or a Woodpecker in a Louisiana swamp may have his habitat inundated by salt water from the gulf. This affects both the birds’ homes and their food supply.

So let’s keep both people and birds in our thoughts as hurricanes develop, which they certainly will.