I wonder what sort of GPS loggers/trackers are used on birds, and where can you buy them? I presume they log at a rather low frequency, ie only 1 point per hour or day, which would make a big difference to battery life (but be less useful for cycling).
OP, Maybe a Garmin Forerunner would fit the bill?
Most of the Forerunners only have about 10 hours of battery life, so probably not very useful.
For a watch, the Garmin Fenix can do up to 50 hours of logging, but that's a less detailed track, ie about 1 point per minute. And it is rather expensive and complicated.
I think some sort of simple GPS logger would be best. I'm not sure if that Qstarz BT-Q818XT in the original post is actually a logger, it seems its just a Bluetooth GPS receiver, you would need a separate device (ie a phone) to record a track. Qstarz do make a few models of GPS loggers, eg BT-Q1000XT.
http://www.qstarz.com/Products/GPS%20Products/BT-Q1000XT-F.htmIt can record up to 400,000 points, and 42 hours battery life. I'm not sure about that model, but it seems some of the Qstarz loggers use a standard Nokia battery, so you could carry a few spares.
There's plenty other brands with similar things. This list on the OpenStreetMap wiki might help:
http://wiki.openstreetmap.org/wiki/GPS_reviews