as a short answer without having seen your lease I have to say I would assume that your responsible for said repairs. Although I am not admitted in TX the general rule is that such damage is not the landlords responsibility.I would suggest you consult your lease to see if it covers such an issue, than you may want to contact an attorney if the language leads you to believe your covered. You should also look into how the squirrel got inside, if it was because of a lack of something that's the landlords responsibility that may help you get the damage covered. Good luck