referencing namespace for JSON in ASP.NET MVC

I am trying to using json for my repository.cs but it keeps giving me the error "does not exist in current context". I think I am missing a namespace, but I am not sure which one to use. I have tried using the namespace "using system.web.mvc" but it only corrects the "JsonRequestBehavior" and gives an error message on "Json" that says "does not exist in current context"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

using Dapper;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;
using Mis324Assignments.Models;

namespace Mis324Assignments.DataRepository
{
    public class BirdRepository
    {
        private SqlConnection connection;

        //Constructor to handle connection    
        public BirdRepository()
        {
            string connectString = ConfigurationManager.ConnectionStrings["Birds"].ToString();
            connection = new SqlConnection(connectString);
        }

        //To view all person details using generic list       
        public List<BirdModel> GetRandom()
        {
            using (IDbConnection db = connection)
            {
                string sql = "SELECT TOP 4 Id, Name, ImageName, Description FROM BirdDetails ORDER BY newid()";
                List<BirdModel> birds = db.Query<BirdModel>(sql).ToList();
                return birds;
            }
        }

        //Get one person by id (for update & details)
        public BirdModel GetOneBird(int id)
        {
            using (IDbConnection db = connection)
            {
                string sql = "select Id, Name, ImageName, Description FROM BirdDetails where id = @Id";
                //need to parameterize ID to avoid sql injection attacks.
                BirdModel bird = db.Query<BirdModel>(sql, new { id }).SingleOrDefault();
                return bird;
            }
        }

        public List<ColorModel> GetColors()
        {
            using (IDbConnection db = connection)
            {
                string sql = "SELECT ColorID, Name FROM Colors ORDER BY Name";
                List<ColorModel> colors = db.Query<ColorModel>(sql).ToList();
                return colors;
            }
        }

        public List<BirdModel> GetByColor(string colorID)
        {
            using (IDbConnection db = connection)
            {
                string sql = "select d.Id, d.Name, d.ImageName " 
                            +" from BirdDetails d, birdColors c " +" where d.Id = c.Id " 
                            +" and c.ColorID = @colorID " 
                            +" order by d.Name";
                List<BirdModel> birds = db.Query<BirdModel>(sql, new { colorID }).ToList();
                return birds;  

            }
        }

        public List<BirdModel> SearchName(string id)
        {
            using (IDbConnection db = connection)
            {
                string wildcard = '%' + id + '%';
                string sql = "select Id, Name, ImageName from BirdDetails where Name like @wildcard";
                List<BirdModel> birds = db.Query<BirdModel>(sql, new { wildcard }).ToList();
                return Json(birdRep.SearchName(id), JsonRequestBehavior.AllowGet);
            }
        }
    }
}