Here is my own java solution. Please rate if you don't mind. :)

public static int birthday(List s, int d, int m) {

    int count = 0;

    for(int i = 0; i < s.size(); i++){                      
        int squaresSum = 0;

        for(int j = 0; j < m; j++){                
            if(j+i < s.size()){                    
                squaresSum += s.get(j+i);
            }               
        }

        if(squaresSum == d){
            count++;
        }
    }

    return count;   
}

}