We know of no organised birding tours to Eritrea.
Contact Haile Amanuel in Massawa firstname.lastname@example.org for birding in Eritrea.
See the Bradt Guide to Eritrea 2002 edition. Further details are available at http://www.africaguide.com/country/eritrea/.
Safety issues encountered are no different from those met in many other African countries. Guidebooks, travel companies and websites provide much of the advice one needs, but some key points warrant repetition here. (1) be aware of the risk of malaria, seek current advice, sleep in a sealed tent or under a net and take prophylaxis as recommended. (2) always ensure you have sufficient water and some method of purification (even if this comprises a pot and a campfire for boiling). (3) do not underestimate the danger of being in the sun too long. Ensure you use sun-block and drink plenty of water, and wear a hat. (4) The incidence of Aids is high. (5) Ensure that you take a reasonably-equipped first-aid pack with you including supplies of hypodermic and suturing needles.