DoWhat, let's see if I can help here.
(And I'm not speaking directly at anyone or pointing fingers...just trying to educate)
Many people do not really realize that mosquitoes are a public health threat and should be a concern to all citizens. Many people just blow it off as a simple nuisance. Varieties of mosquitoes carry varieties of diseases.
This link
Mosquito Control is for Calvert County Mosquito Control Program's website. You may find some valuable information here.
With the Asian Tiger mosquitoes, the only way to get rid of them is to get rid of all standing water. When we go to communities for inspections, we can walk into the cleanest communities, yards and homes. BUT, all these particular mosquitoes need is a bottle cap of water to breed or a tiny amount of water in a MAN MADE CONTAINER! Tiger mosquitoes will not breed in mud, dirt, etc. I'm serious here! Mosquities instinctively now what holds water. They lay their eggs just above where they know water has sat in the past. When it rains, and that container floods, the mosquito eggs will go through the process of development and become biting adults. The BEST way to control these mosquitoes is to get rid of the breeding sites. You kill many more moquitoes in a flower pot tray, tire, bird bath, etc. as larva, then you will with a spray truck. Most people served by our profession don't understand that because they don't understand the biology of the mosquito.
Imagine this....you have a flower pot on your deck that unknowningly is breeding mosquitoes, you go out on the deck to grill a steak, MISS mosquito (females need blood meal for their eggs to develop) bites you on the leg, by the time you realize you've been bit, she is gone and soon to lay eggs in that flower pot to wait for the rain so many more will come and bite you later, therefore creating many more adults that will lay that many more eggs. It is a vicious cyclye. If you don't get rid of the containers, you cannot break the pattern. Now, with all of that said.....many homeowners often cannot find their breeding sites on their own. (I had a hose reel that had one leaf stuck in a drain hole....it held about 1 inch of unseen water and had hundreds of larva in it) It happens to the best of us. It is all about education.
A couple of suggestions. If you use outside lighting, turn off the lights as the mosquitoes are attracted to bright light. Change to yellow bulbs. If you purchase and use some type of 'mosquito magnet machine', put it on the edge of the property, not next to the deck.
DoWhat, you say you have a creek bed behind the house. This type of environment would not breed tiger mosquitoes, but possibly other types of mosquitoes if there is standing/stagnant water. As long as the water is moving, it should not breed. Bats - eh....there are much bigger insects a bat would rather eat than a tiny mosquito.
Also, it is best to verify what type of mosquito you are dealing with. There are other mosquitoes that look similar to the asain tiger (with black and white stripe) but are more aggressive. The 'tigers' generally stay below the knee and are very skittish. You go to swat them, they back away and then come back. Others are relentless and will even fly in your ears and up your nose.
The State of Maryland has cut funding to many programs througout the State, including mosquito control. Less staff, more paperwork and more financial burden on the providers, whether it is a County or State run program.
You can also call your local program, ask if they can come and do an inspection to help you identify and resolve your problem.
I hope this has helped some!
On a side note, Avon has a wonderful mosquito repellant line for adults and children over the age of 2. There is also a natural repellant that I will be trying in a few weeks called Skedattle.