An important part of wildlife photography is understanding the conditions you'll encounter when visiting a particular location. I'm often visiting wildlife locations with tidal bodies of water, such as harbors, rivers, or tidal marshes, such as you can find in the John Heinz National Wildlife Refuge.
Knowing the tides is important along harbors and tidal marshes, so you'll know what kind of birds you might expect to see at various locations you're visiting. If you want to maximize your chances of seeing smaller shore birds such as sandpipers yellowlegs, and dowitchers, you try to visit during low tides.
I use the iPhone app Tide Graph to calculate and identify tides at US locations. It's the best tide calculator for smartphones I've found. At this time, Tide Graph is not available for the Android operating system.
“The cyclical movement of the Earth's tides are caused by a combination of the gravitational forces of the sun and moon as well as the shape of the coastal region. Unlike simple tide clocks that you can buy in novelty stores, more accurate tide predictions use special data gathered by instruments located at each tide station. The data from these measurements are used to determine the harmonic components which then feed into the mathematical algorithms which predict tides for the future. The end results are tested for accuracy and adjustments are made as necessary.The app really helps you understand the conditions of tidal areas in which you're photographing, and best times for your visit based on those conditions.
Tide Graph has US owned Tide Stations Only. An internet connection is required to get the latest tide graph.”
I'm always on the lookout for new photography apps for my iPhone and for Android apps too. If you have a good one to suggest, contact me. If I like it after testing, I'll give you credit for your suggestion in my Blog article about it. Thanks.