Birdlife Australia hosts a backyard bird count each year.  Students can register to be a counter and observe, count and tally the types of birds that come into their yard in a 20 minute timeframe.

Aussie Backyard Bird Count

The data can be then brought to the classroom and the students can combine it, sort it, arrange it and work on different ways to represent it and interpret it.  This could be done across year levels or as a whole school initiative as well!

This easily connects to science as well as maths, considering life cycles, habitats, adaptations, and interrelationships.