How to label sound events in noisy .wav files I'm trying to find a way of automatically identifying birdsong in phone-recorded sound files (1min long). Currently the algorithm I'm using doesn't label all of the events I want it to. (it is designed for non noisy audio files).  

I don't have much experience in DSP. I'm hoping that upon looking at my wave-forms someone may have an idea of how to pick out these 'birdsong events'!
I've shown one of the waveforms. The rest can be seen here: imgur.com

Any method would be appreciated!

I've thought about applying a noise reduction algorithm but I suspect this could just interfere with things.
Here is a link to the algorithm I'm using in case you're interested: Github/kylemcdonald

The labelled events are the cross hatched ones.


Thanks in advance for taking the time to look at this!
Automatic detection of birdsong is a well studied problem in machine-learning applied to ecoacoustics/bioacoustics. State of the art methods use Convolutional Neural Networks on spectrograms. In binary classification of bird/no-bird they reach AUC ROC of around 0.90 in noisy and mismatched conditions. The DCASE2018 Bird Audio Detection challenge is a good starting point. Open-source code is available for many of the systems, including the challenge winner. Several of the systems could be adapted to Audio Event Recognition to give time-information of predictions.

Note that to verify your approach is working well, you should always also have a manually labeled test-set.