diff --git a/Bird.py b/Bird.py
new file mode 100644
index 0000000..39f31e2
--- /dev/null
+++ b/Bird.py
@@ -0,0 +1,73 @@
+'''
+Function:
+	定义bird类
+Author:
+	Charles
+微信公众号:
+	Charles的皮卡丘
+'''
+import pygame
+import itertools
+
+
+'''bird类'''
+class Bird(pygame.sprite.Sprite):
+	def __init__(self, images, idx, position, **kwargs):
+		pygame.sprite.Sprite.__init__(self)
+		self.images = images
+		self.image = list(images.values())[idx]
+		self.rect = self.image.get_rect()
+		self.mask = pygame.mask.from_surface(self.image)
+		self.rect.left, self.rect.top = position
+		# 竖直方向运动所需变量
+		self.is_flapped = False
+		self.down_speed = 0
+		self.up_speed = 9
+		# 切换bird形态
+		self.bird_idx = idx
+		self.bird_idx_cycle = itertools.cycle([0, 1, 2, 1])
+		self.bird_idx_change_count = 0
+	'''更新'''
+	def update(self, boundary_values, time_passed):
+		# 竖直方向的位置更新
+		if self.is_flapped:
+			self.up_speed -= 60 * time_passed
+			self.rect.top -= self.up_speed
+			if self.up_speed <= 0:
+				self.unsetFlapped()
+				self.up_speed = 9
+				self.down_speed = 0
+		else:
+			self.down_speed += 40 * time_passed
+			self.rect.bottom += self.down_speed
+		# 判断bird是否因为撞到上下边界而挂掉了
+		is_dead = False
+		if self.rect.bottom > boundary_values[1]:
+			is_dead = True
+			self.up_speed = 0
+			self.down_speed = 0
+			self.rect.bottom = boundary_values[1]
+		if self.rect.top < boundary_values[0]:
+			is_dead = True
+			self.up_speed = 0
+			self.down_speed = 0
+			self.rect.top = boundary_values[0]
+		# 切换bird形态模拟以模拟扇翅膀效果
+		self.bird_idx_change_count += 1
+		if self.bird_idx_change_count % 5 == 0:
+			self.bird_idx = next(self.bird_idx_cycle)
+			self.image = list(self.images.values())[self.bird_idx]
+			self.bird_idx_change_count = 0
+		return is_dead
+	'''设置为飞行模式'''
+	def setFlapped(self):
+		if self.is_flapped:
+			self.up_speed = max(12, self.up_speed+1)
+		else:
+			self.is_flapped = True
+	'''设置为下落模式'''
+	def unsetFlapped(self):
+		self.is_flapped = False
+	'''绑定到屏幕'''
+	def draw(self, screen):
+		screen.blit(self.image, self.rect)
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