One of the biggest helps I get is from the customers without them knowing it. When A customer tells me that they have been hearing a squirrel running around, then one day there is a lot of noise, fast running, noise in places that they normally do not hear the squirrel, frantic running and so on. Then, they tell me, that the noise has stopped, and they think the squirrel has left. That is a good sign that the female has dropped her young. If the customer tells me that a few days ago the squirrel put a quarter to half dollar size hole in the ceiling, before all this took place, I am 90 % sure that she has dropped. I will tape the entry to see if there is activity, it seems that the female will hole up for a day to a few days nursing the pups. if she does leave them she is fast. food is the last thing on her mind the first day or so. also she will avoid a lot of stuff that may make her uneasy. also if I catch a female that is really banging her self up in the trap really rubbed nose and forehead down to the meat, then 9 out of 10 times she has young in there. check her good for nursing. remember when pups are only a day or so old, she will not show a lot of milk. most of the time the hair is only parted in a circle away from the nipples. also after a few day of nursing the nipples may look black if she has been in the trap for any amount of time. I think it has something to do with the blood and bruising may be wrong on that. also another sign is the hair in the front leg pits and sides will be gone. this only seems to happen in the colder first time frame for dropping. I don't see it to often in the June brithing phase