Birding in winter in texas and Arizona

Hi everyone, I and my partner and planning a trip to big bend national park for the last two weeks of December and were wondering about how the birding will be at that time of the year. its part of a larger road trip (dallas to seattle in 3 weeks) so we can also stop at saguaro national park if the birding will be good at the time. any advice or insights will be helpful.

for now, we were thinking of making our first stop at big bend, then saguaro, then desert NWR and the figure out if we wanna make any more stops on the way to seattle.