The opinion of the court was delivered by: Colleen Kollar-kotelly United States District Judge
Plaintiff Wildearth Guardians brings this suit for declaratory and injunctive relief against Defendant Dick Kempthorne in his official capacity as Secretary of the Interior. Plaintiff filed its original Complaint in this matter on March 19, 2008, alleging that Secretary Kempthorne has failed to comply with his mandatory duty, under the Endangered Species Act ("ESA"), 16 U.S.C. §§ 1531 et seq., to make a preliminary "90-day finding" on two separate ESA "listing" petitions submitted by Plaintiff. Subsequent to filing its Complaint in the above-captioned case, Plaintiff submitted a separate petition to Defendant requesting that a small subset of species, all of which had been included in one of the two petitions at issue in the original Complaint, be given protection on an emergency basis, which request Defendant subsequently denied. Plaintiff now moves the Court for leave to amend its Complaint for clarification purposes and to supplement the Complaint to include a new claim against Defendant stemming from its denial of Plaintiff's emergency petition. Although Defendant does not object to Plaintiff's request for leave to amend, Defendant does oppose Plaintiff's request for leave to supplement the Complaint with a new claim. After a thorough review of the parties' submissions, applicable case law, statutory authority and regulations, the Court shall GRANT IN PART and DENY IN PART Plaintiff's  Motion for Leave to Amend and Supplement the Complaint. Specifically, Plaintiff's Motion shall be granted as to its request for leave to amend, but shall be denied as to its request for leave to supplement, for the reasons set forth below.
In 1973, Congress enacted the ESA, 16 U.S.C. §§ 1531 to 1544, "to provide a means whereby the ecosystems upon which endangered species and threatened species depend may be conserved, [and] to provide a program for the conservation of such endangered species and threatened species."*fn1 16 U.S.C.§ 1531(b). In order to receive the Act's protections, a species must be "listed" as endangered or threatened by the Secretary of the Interior.*fn2 The determination of whether a given species should be listed as endangered or threatened under the ESA may be made either on the initiative of the Secretary via the "candidate process" or in response to a citizen's request via the "petition process." See id. §§ 1533(a)(1), 1533(b)(3). Once a species is listed, through either the candidate process or the petition process, the ESA provides that the Secretary "shall issue such regulations as he deems necessary and advisable to provide for the conservation of such species." Id. § 1533(d).
In determining whether to list a species, the Secretary determines whether the species "is a threatened or endangered species because of any of the following factors:"
(A) the present or threatened destruction, modification, or curtailment of its habitat or range;
(B) overutilization for commercial, recreational, scientific, or educational purposes;
(C) disease or predation;
(D) the inadequacy of existing regulatory mechanisms; or
(E) other natural or manmade factors affecting its continued existence.
Id. § 1533(a)(1). This determination must be made "solely on the basis of the best scientific and commercial data available to [the Secretary] after conducting a review of the status of the species and after taking into account those efforts, if any, being made by any State or foreign nation . . . to protect such species." Id. § 1533(b)(1)(A).
As is relevant to the instant case, any "interested person" may petition to have a species listed as threatened or endangered pursuant to the petition process referenced above. Id. § 1533(b)(3)(A). Once a petition is received, the Secretary is required to determine whether the petition presents "substantial scientific or commercial information" indicating that the petitioned action may be warranted. Id. The ESA specifies that the Secretary is required to make that finding-known as the "90-day finding"-within 90 days after receiving the petition, "[t]o the maximum extent practicable." Id.
The 90-day finding is published in the Federal Register. Id. § 1533(b)(3)(A). If the Secretary determines that the listing is not warranted, the listing process for that species is terminated. See id. However, if the Secretary determines that the petitioned action is warranted, the Act provides that the "Secretary shall promptly commence a review of the status of the species concerned." Id. Within 12 months of the receipt of the petition, the Secretary is required to make a finding-known as the "12-month finding"-stating whether the petitioned action is (a) warranted; (b) not warranted; or (c) warranted but precluded by other listing activity. Id. § 1533(b)(3)(B). Under the normal listing procedures, the Secretary lists a species by promulgating a regulation after undertaking formal rulemaking pursuant to the procedures set forth in the ESA and the Administrative Procedures Act ("APA"), 5 U.S.C. § 701 et seq. See id. § 1533(b)(4). However, in situations where there exists an "emergency posing a significant risk to the well-being of any species of fish or wildlife or plants," the ESA authorizes the Secretary to bypass ESA and ...