I've thought it would be great to use standalone hardware to gather weather data even if the Squirrel Café is closed for our guests due to software updates or periodic maintenance necessary.
Quickly I've decided to use an ESP8266 to gather environmental data. The board I've chosen is an inexpensive Witty Cloud board for about 3.00 $ from China shipping included with an LDR onboard to measure light levels. To read temperature and humidity I've attached a commonly used DHT22 sensor.
Furthermore I've decided to decouple the fields of the ThingSpeak channel I'm using now to differentiate periodic tasks like reading environment data from events like opening the feeder lid. The weather data is read every 5 minutes which should be sufficient.
On GitHub you'll find the Witty Cloud Arduino Sketch for gathering and posting data to ThingSpeak.