The Numbers of These Days

I live my summer Pennsylvania life in certain numbers:

The baby robins take 13 days to fledge.
They will leave the nest, therefore, in 3 days. 
They will train in the garden for 3 weeks with their parents nearby to teach proper feeding, flying, and general Robin living.
I will replace the hummingbird feeder nectar every 3 days. 
I have seen 3 kinds of hummingbirds at my feeder (only 3 have have been reported in Pennsylvania!): the Ruby-throated Hummingbird–the male boasts that ruby-red throat, a white collar, an emerald green back and a forked tail while the female wears an emerald green coat with white, black, and green tail feathers; the Rufous Hummingbird, and what I think is the rare Calliope (a very small hummingbird with pink stripes around his neck).
In 72 days, I will have grown a watermelon.

I love waking up to numbers like these.