Taking photos when an IR sensor detects motion?

Question

I'm trying to write a program in python 3.4 for my Raspberry Pi that will take some photos when motion is detected from an IR sensor ( A bird table in this case).

The camera and IR sensor are working fine but I'm trying to figure out how to just take a few pictures when a bird triggers the sensor and then put the program to sleep for a bit and then take some more photos later when another bird arrives. The problem with my program is that it just continually takes photos non-stop when any motion is detected. Any ideas. Thanks.

from gpiozero import MotionSensor
import time
from datetime import datetime
from picamera import PiCamera
from time import sleep

camera=PiCamera()

pir = MotionSensor(4)
while True:
    if pir.motion_detected:
        sleep(1)
        filename = datetime.now().strftime("%Y-%m-%d_%H.%M.%S")
        camera.capture('/home/pi/Desktop/images/'+filename +'.jpg')
        print('picture taken')

Answer 1

Use

pir.wait_for_motion()
# Code here
pir.wait_for_no_motion()
# Sleep