Ornithology: Birds Lecture Notes

These flashcards cover essential concepts, definitions, and unique characteristics related to ornithology, focusing on bird diversity, adaptations, physiology, and behavior.

What is the total number of bird species described worldwide?

Over 10,400 species.

What are the unique features of birds?

Feathers, modified forelimbs as wings, hindlimbs adapted for various functions, and keratinized beaks without teeth.

How does migration benefit birds?

It increases breeding space and reduces territorial behavior.

What distinguishes Paleognathae from Neognathae?

Paleognathae are flightless birds with a flat sternum; Neognathae are flying birds with a keeled sternum.

What are contour feathers?

They give the bird its form and extend beyond the body as flight feathers.

Why must birds molt?

To replace fully-grown feathers, which are dead structures.

What are pneumatized bones?

Light, delicate bones with air cavities in birds, making them strong and rigid.

What role does the proventriculus serve in a bird's digestive system?

It secretes gastric juice.

What type of heart do birds have?

A 4-chambered heart.

What adaptations do birds' lungs have for flight?

They have tube-like parabronchi for continuous air flow and nine interconnecting air sacs.

Describe the nesting behavior of birds.

Some build elaborate nests, while others lay eggs on the ground; they exhibit different parental care methods.

What is the main function of bird beaks?

They reveal food habits and adaptability to different diets.

How does a bird's reproductive system differ from other animals?

Many male birds lack a penis and copulate by bringing cloacal surfaces in contact.

What is monogamy in birds?

Over 90% of bird species mate with one partner each breeding season.

What is polygyny?

One male mates with many females during a breeding season.

How do Altricial and Precocial birds differ in development?

Altricial birds are naked and need care at birth, while Precocial birds are covered in down feathers and can feed themselves shortly after hatching.

What physiological demands do bird muscles face?

They must support the mechanics of flight, particularly in the musculature of the wings.

What material forms bird beaks?

Keratin.

What is a keeled sternum and its significance in birds?

A strong, bony ridge on the breastbone (sternum) of flying birds (Neognathae) that serves as the attachment point for powerful flight muscles.

What is the primary function of parabronchi in bird lungs?

To facilitate continuous, one-way airflow through the lungs, ensuring highly efficient oxygen exchange.

What are air sacs, and how do they aid bird respiration?

Nine interconnecting, thin-walled sacs connected to the lungs that act as bellows to move air through the parabronchi, ensuring a continuous supply of fresh air.

What is the "cloacal kiss" in bird reproduction?

The method of copulation where many male birds bring their cloacal surfaces into brief contact with the female's to transfer sperm, as they lack a penis.

What are the characteristics of an Altricial chick at hatching?

They are typically naked, blind, helpless, and entirely dependent on parental care for food and warmth.

What are the characteristics of a Precocial chick at hatching?

They are covered in down feathers, have open eyes, are relatively mobile, and can independently feed themselves shortly after hatching.