government that makes a profit for taxyers as well as ma ny small business exporters. but new a congressional showdown is looming for funding over the united states export-import bank, and that might put american jobs in danger. wyatt andrews takes a look. >> one of the bright sparks in the economy of northwest texas. is the demand for american-made crop dusters, orders are literally taking off here at the air tracker corporation in olney, texas. 44 custom-made planes are in production for export to farmers in south america. >> we export airplanes all over the world, and those exports create jobs in olney, texas. >> but despite the jobs and the

rush of orders, air traffic officials are worried about washington. >> we are at risk because of what's going on in congress. >> at risk because of a quiet debate in congress over this, the refunding of the united states' export-import bank. exim, as it's called, is a taxpayer-financed bank that makes loan to foreign buyers of american products. without new funds, the bank could stop lending at the end of the month, which would stop the sale of the crop dusters. >> it impacts us. it impacts olney, texas. >> normally the exim bank is seen as a washington success story. last year the bank helped finance almost $33 billion in exports and returned a profit to taxpayers. why the controversy? that boils down to boeing versus delta. for a decade, the exim bank has helped boeing sell hundreds of planes at favorable lending rates to foreign airlines that

compete with delta. the cost advantage, delta claim, helped those foreign carriers win more passengers and caused the loss of up to 7,500 u.s. jobs. six republican senators, including tom coburn of oklahoma, say the exim bank is bound by law to study the harm it does to other u.s. employers. >> this bill isn't going to move until we have some teeth that requires export-import bank to do what the law says, and they have flouted it, ignored it and don't care. >> exim officials deny any harm to dealta. they point out if foreign airlines didn't buy from boeing, they would have bought planes in europe. >> if it's bought by airbus instead of boeing, they may go that way for next ten years. that's the real risk. >> caught in the middle are not just the 44 crop dusters in texas. across the country hundreds of export businesses fear the loss of millions in sales and thousands of jobs.

wyatt andrew, cbs news, washington. >> we'll be back.

old. this year it is very early. thousands of cherry trees are blooming in the nation's capital. the season to peak will be this tuesday, march 20th because of unusually warm weather in d.c. finally tonight, the warm weather is also luring migrating birds back north earlier than expected. those birds will sing to find a mate. but it turns out the language of love is not universal. here's bill plante. >> think of this as march madness, just a different kind. >> kind of cute. >> it's the march migration of birds, starting their seasonal journey looking for a mate. [horn honks] >> but for a bird

setting out to find a partner in the urban jungle is tough. echoes of tall buildings can confuse the bird's hearing. a conservation scientist peter marra has discovered that urban surroundings actually change how birds call out. >> just like you when you're in a bar or if you're out on the street and a siren goes by, you have to shout or you have to change your own voice so someone else can hear you. >> working with researchers at the smith soabian, marra found that increased noise alsoers the pitch of an urban bird compared the that of its country cousin. from his office at washington's national zoo, he demonstrates with the carolina wren. >> so let's listen to the real song right now. [birds singing] >> now let's listen to the carolina wren in an urban environment. [birds singing] >> the range of the urban bird is more narrow and the pitch of its song has gone up. here is the carolina chickadee. >> here's a chick dee in a rural

environment. [birds singing] >> now let's listen to that poor little chickadee in an urban environment. >> that heightened pitch has scientists wondering will city birds be able to find love if their country cousins refuse the mate because they don't recognize calls from the urban hood? >> noted birder harrison glasgow, it comes down to the adaptability of nature. >> nature simply wants a balance. and the birds that live in the city have to achieve that balance. >> marra says more research is in the works to determine whether urban birds have simply adapted to the stress of city living and what happens when mother nature passes down a different tune to future generations. bill plante, cbs news, washington. >> that is the "cbs evening news" tonight. i'm jeff glor. cbs news in new york. good night. ,,,,