Site Designation and Establishment of Conservation Measures
Birds Directive - Obligations of special conservation measures
1. The species mentioned in Annex I shall be the subject of special conservation measures concerning their habitat in order to ensure their survival and reproduction in their area of distribution.
In this connection, account shall be taken of:
- (a) species in danger of extinction;
- (b) species vulnerable to specific changes in their habitat;
- (c) species considered rare because of small populations or restricted local distribution;
- (d) other species requiring particular attention for reasons of the specific nature of their habitat.
Trends and variations in population levels shall be taken into account as a background for evaluations.
Member States shall classify in particular the most suitable territories in number and size as special protection areas for the conservation of these species in the geographical sea and land area where this Directive applies.
2. Member States shall take similar measures for regularly occurring migratory species not listed in Annex I, bearing in mind their need for protection in the geographical sea and land area where this Directive applies, as regards their breeding, moulting and wintering areas and staging posts along their migration routes. To this end, Member States shall pay particular attention to the protection of wetlands and particularly to wetlands of international importance.
3. Member States shall send the Commission all relevant information so that it may take appropriate initiatives with a view to the coordination necessary to ensure that the areas provided for in paragraphs 1 and 2 form a coherent whole which meets the protection requirements of these species in the geographical sea and land area where this Directive applies.
4. In respect of the protection areas referred to in paragraphs 1 and 2, Member States shall take appropriate steps to avoid pollution or deterioration of habitats or any disturbances affecting the birds, in so far as these would be significant having regard to the objectives of this Article. Outside these protection areas, Member States shall also strive to avoid pollution or deterioration of habitats.
Article 4 (1) and (2) requires the Member States to provide the special protection areas referred to therein with a legal protection regime that is capable, in particular, of ensuring both the survival and reproduction of the bird species listed in Annex I to the Directive and the breeding, moulting and over-wintering of migratory species which are regular visitors, albeit not listed in that Annex. 
Article 4 (1) requires Member States, if species mentioned in Annex I occur on their territory, to classify the most suitable territories in number and size for their conservation as special protection areas, an obligation which it is not possible to avoid by adopting other special conservation measures.
The provisions of directives must be implemented with unquestionable binding force, and the specificity, precision and clarity necessary to satisfy the requirements of legal certainty. The principle of legal certainty requires appropriate publicity for the national measures adopted pursuant to Community rules in such a way as to enable the persons concerned by such measures to ascertain the scope of their rights and obligations in the particular area governed by Community law. With regard to maps demarcating SPAs, they must be invested with unquestionable binding force.
Once an area has been designated under the Birds Directive, a strict legal regime applies. Originally the Birds Directive had its own legal regime for SPAs, laid down in Article 4 (4) of the Birds Directive. This was a very strict regime which was replaced in 1992 by the regime that was adopted for SACs under the Habitats Directive. Since then, Article 6 of the Habitats Directive has applied to all of these areas (including the ones designated under the Birds Directive).