Yellow Cucumbers? My cucumbers are growing pretty good, but they are turning yellow, especially...

My cucumbers are growing pretty good, but they are turning yellow, especially at the top where on earth the connect to the plant. Any idea whats causing and what I can do to prevent it.
What perennials/bulbs can I plant that will bloom...
Answers:    are they over ripe?
EDIT:::::
or over watered or shaded '
it could be a nutrient fewer
give this site a look over maybe it will back

http://www.urbanext.uiuc.edu/veggies/cuc...

there is a possibility it is just the type of cucumber
theres not a casual that it is a squash is there?
Orchid aid?
Yes, they are overripe.