Question

Trace out similarities between birds and mammals.

Answer 1

Birds and mammals both have different structures and functions but sometimes the functions are the same. They both have certain similar behavioral characteristics along with the function of certain specialized body organs.

Complete answer
The similarities between birds and mammals are as follows:

Birds	Mammals
They constitute a backbone, thus categorized under the vertebrates.	They also constitute backbone, thus categorized under the vertebrates.
They are warm-blooded animals thus can maintain their body temperature resulting in homeostasis.	They are also warm-blooded animals thus can maintain their body temperature resulting in homeostasis.
They can survive even in the coldest of temperature due to homeostasis.	They may also survive even in the coldest of temperature due to homeostasis.
The heart present in them is found to be four-chambered.	The heart present in them is also found to be four-chambered.
The blood is composed of red blood cells and white blood cells that help in the maintenance of the immune system.	The blood here also is composed of red blood cells and white blood cells that help in the maintenance of the immune system.
The red blood cells contained red haemoglobin pigment that helps in the transportation of oxygen in various parts of the body.	The red blood cells here also contained red haemoglobin pigment that helps in the transportation of oxygen in various parts of the body.
They take care of their children by feeding them from beak to beak.	They also take care of their children by feeding them through lactation.
They have enhanced and developed skills of hearing, vision, communication, metabolism, etc.	They also have enhanced and developed skills of hearing, vision, communication, metabolism, etc.

Note:
The birds and mammals are found to have some similar features. On the basis of the evolutionary history, they both are found to have a connecting link between them called Seymouria. Both of these groups are similar due to the occurrence of the evolution in them recently.