We always have a knife & also a compass when in woods following trails on the map (French maps are not great & we've been lost a few times). Also a mobile phone in case of accidents. Always a bottle of water in case we get lost despite the compass. We never see any other birders when we're out!
Compass: Yes
Knife: No
Torch: Yes
Small First Aid Kit: Yes
Disposable Gloves (For Handling Sick or Injured Birds): Yes
Mobile Phone: Yes
Finally, and most importantly of all...
Live Mealworms (Robins, for the feeding of): Always!