Before somebody starts trying to smugly draw some parallel with urban and rural humans, the finches have natural selection weeding out the weak (or in this case less intelligent). This isn't happening with people.
Sure. Even though humans are still shaped by natural selection, we now have to consider that we are evolving in a balance between culture and biology. http://www.sciencemag.org/news/2012/04/natural-selection-sti... (This article has some interesting (and controversial) remarks on the role of natural selection in humans).
"One such test involved setting a dish of food and timing how long it took the finch to eat it;"
How is this a test of "intelligence"? Biology, metabolism and food drive maybe, but "intelligence"?
The researchers wanted to test whether city birds had 'higher boldness, reduced neophobia, and enhanced problem-solving and learning skills'. These specific test was done to see whether they could guarantee reproducibility of the results. Something like a control
that still makes no sense as far as 'intelligence' goes. First off, rural and urban birds have different overall diets. if you stick a french fry in front of a rural bird, it might not know its supposed to be 'food'. Same can be said with water-bugs and urban birds. there are too many factors to consider - though they could have and just not reported the specific metrics.