Ornithology Lab practical 1 study guide

How do birds make an egg?

mating and the touching of cloacas

Amniotic Egg (Cross Section)

Tetrapod’s freedom from water

Yolk (Cross Section)

energy supply

lipids, protein, water 

hormones and other health

What leads to the latebra?

germinal disc 

What is the vitelline membrane?

early steps of the stomach and inetentions

absorbed by embryo

Albumen (Cross Section)

water and protein

shock absorption

temperature control

Germinal Disc (Whole Egg)

located on the latebra

holds the blastoderm once fertilized 

Chalaza (Whole egg)

rope-like protein structures within the egg

anchors yolk and protects it from the shell

Energy needed vs. Yolk size

relative yolk varies across species depending on species needs

Altricial

“helpless hatchling”

Precocial

“independent hatchling”

Palisade (eggshell)

calcium carbonate structure, forms the main thickness of the shell and provides strength 

Cones (eggshell)

used for calcium transport

Chorioallantois (eggshell)

vascular transport system

Embryo will begin developing these structures within the first 24 hours of incubation:

• GI Tract

• Vertebral column

• Nervous system

• Head

• Circulatory vessels

• Formation of the eye

What happens during the 2nd day of incubation?

the heart and ear begin to form, and the heart begins to beat

What happens during the 3rd day of incubation?

the amnion, beak, legs, wings, and allantois begin to form

What happens during the remainder of the first week of incubation?

the tongue, reproductive organs, and egg tooth begin to form

What occurs during the second week of incubation?

feathers, podotheca, and claws begin to develop

Podotheca

keratinized epidermis forming scales that extends from the tarsometatarsus to the toe extremities 

What occurs during the third week of incubation?

nails, beak, and podotheca harden

beak turns to the air cell

yolk sac begins to resorb into the body

embryo grows to fill the entire egg except the air cell

hatching occurs at approximately 21 days 

How does natural incubation vary?

there are many methods depending on the species

Asynchronous Hatching

form of natural incubation

bird eggs in a clutch hatch over the course of several days as opposed to all at once

Synchronous Hatching

form of natural incubation

when the eggs in a clutch hatch hours apart from each other, even though they were laid days apart

What are necessities for bird enclosures?

• natural lighting

• vitamin D

• large flight space

• double doors/double containment 

• foliage, nest materials

Mew Enclosures

outdoor bird enclosures, smaller size, natural foraging may seep in

What do some bird species need?

specific fencing

Indoor Exhibits

sterile, easy to clean, drains are usually kept on the floor

Aquatic Exhibits

• water temperature

• water chemistry

• how water gets into the enclosure

• life maintenance 

• water depth 

• ability to clean and manage the windows 

• important to make sure drains are in the right place 

What should you have equipped if you keep birds in an open space?

leather straps/jesses