uses his plumage to guard the recently hatched chicks               

feeds the eggs through a crack in the nest        

doesn´t hatch the eggs by keeping them warm with his own body

doesn´t help the female until she has enclosed herself in the nest                       

bird                    

seal                      

bear

chicken                

the geographic features of the delta are always changing                         

the river, delta, and sea play an important role in building Lousiana´s continental shelf

the delta is being destroyed by the Mississippi River´s depositing sand, silt and clay                     

the sea movement is building a delta on the continental shelf at the mouth of the Mississippi                              

people can put their own ultralights together               

ultralight builders need to have training in aviation

people who fly ultralights have no experience                

an ultralight can be purchased at the airport                    

the female Malabar pied hornbill breaks up the nest after it molts                    

the hole in the tree is so warm it causes the female Malabar pied hornbill to lose its plumage                           

the Malabar pied hornbill´s nest is lined with feathers                              

the female Malabar pied hornbill plucks off its feathers in order to cover the crack in the nest

human energy 

remote control

solar energy

an engine        

petroleum is causing heavy soil erosion and pollution problems

soil erosion, pollution, and petroleum scarcity are critical problems that the nation faces

soil erosion has caused humans to place new demands on heavy crop production

petroleum will be the most critical natural resource problem

because of the frequency of fatal accidents, laws requiring parachutes have been enacted

ultralight pilots can walk away from most of the accidents they are in                    

accident statistics are inaccurate because ultralights are not registered at airports                        

fatal accidents are frequent because of the lack of experienced pilots                      

nurseries have been set up in the delta so that children can take part in aquatic sports in the Bays, lakes and sounds

the delta marshlands is an excellent area for medical people to study diseases caused by Mosquitoes and other insects  

the United States has established nurseries to provide shelter and food for migrating birds

the delta system formed by the Mississippi River is very important for marine life                      

The female is so involved in building her nest that she doesn´t realize she´s locked herself inside it.                

The female has to keep the male from hurting the babies, so he encloses herself in the nest.

The female purposely imprisons herself to lay her eggs.                         

The male is afraid of other males and, therefore, forces his mate into the nest and seals it.