I am working on a project involving analysis of bird sounds and I want to record these sounds in slightly remote locations. It is enough if the device can only record and store them (maybe in an SD card). Are there any devices available that I can readily use or what would be the best way to do this ?
There are plenty of devices that can do this. Simply Google portable recorders. They generally all have a microphone built in. Some have line level inputs, and some can also take XLR inputs and provide phantom power for condenser microphones.
If you don't need the XLR inputs, I can recommend the Zoom H1. It has a stereo microphone, can also take a line level input and is fairly cheap. I have used this to record various foley sounds including bird songs. The sounds save onto an SD card in high quality 24-bit/96 kHz WAV files for analysis on a computer later.
It's best to get a little tripod for it too to stop any handling noise.
Recording birds is not so easy as the level of birds singing can be low compared to other sounds in the environment. If you plan to record in the open, be careful that built in microphones as the one you ususally find on pocket recorders might be subject to wind noise. To deal with wind noise, you don't have much choice but to have a microphone inside a windjammer.
Depending on the use case (ie doing some digital signal analysis on the audio or simply listening to it), you can record the audio files as mp3 instead of wav/pcm. That will allow for longer records on the recording medium. The H1 doc mentions 55 hours in pcm/wav and up to 555 hours in mp3 on a 32Gb card.
But to have the recorder run on battery 50 hours will require to find an external power supply able to support this duration that the included AA battery case will not.