BIOLOGICAL BACKGROUND. The bald eagle (Haliaeetus leucocephalus) is the symbol of the United States and one of North America’s most spectacular birds. It is also one of the most thoroughly studied birds, with perhaps 2,500 articles published on its biology or management (Xxxxxxx 2000). This chapter summarizes some aspects of the bald eagle’s biology, primarily in Florida. Detailed information on the biology of bald eagles throughout their range is found in Stalmaster (1987), Gerrard and Bortolotti (1988), and Xxxxxxx (2000). Distinguishing Characteristics The bald eagle is the largest raptor (bird of prey) that occurs in North America, ranging from 28 to 38 inches in length and with a wingspan from 66 to 96 inches. The largest eagles are found in Alaska and the smallest occur in the southern United States and Mexico (Xxxxxxx 2000). The sexes are indistinguishable by plumage, but females are as much as 25% larger than males. Adults are dark xxxxx with a white head and tail. The eyes, xxxx, legs, and feet are yellow. Juveniles are dark xxxxx overall with white mottling on the belly, tail, and underwings. The eyes are dark xxxxx and the xxxx is xxxx to black. The plumage of sub-adults is highly variable, according to age, with a decreasing amount of white on the body and an increasing amount of white on the head and tail attained with each successive molt. The eyes and xxxx turn yellow during the eagle’s fourth year, and full adult plumage is attained during the bird’s fifth or (usually) sixth year (Xxxxxxx 2000).
BIOLOGICAL BACKGROUND. MIRROR's biological background has two "pillars": 1) recent findings on how the brain represents and recognizes motor actions; 2) studies and models of human sensorimotor development. The first "pillar" refers to one of the most fascinating discovery of the neurophysiology in the last two decades. Neurons located in a frontal region classically considered as motor, in addition to their motor discharge, respond also to the presentation of visual stimuli. Neurons with this property mainly pertain to FEF [13] and ventral premotor areas F4 and F5 [14-18] that, taken together, represent the main target for the inferior parietal lobule projections carrying out visual information. “Mirror” neurons constitute a class of F5 visuomotor neurons that become active when the monkey acts on an object and when it observes another monkey or the experimenter making a similar goal directed action [3, 4]. The visual stimuli most effective in triggering “mirror” neurons discharge are actions in which the experimenter's hand or mouth interacts with objects. The mere presentation of 3-D objects or food is ineffective in evoking mirror neurons discharge. Similarly, actions made using tools, even when conceptually identical to those made by hands (e.g. grasping with a pliers), do not activate the neurons or activate them very weakly. The observed actions, which most commonly activate mirror neurons, are grasping, placing, manipulating, and holding. Most mirror neurons respond selectively to only one type of action (e.g. grasping). Some are highly specific, coding not only the type of action, but also how that action is executed. They fire, for example, during observation of grasping movements, but only when the object is grasped with the index finger and the thumb. Typically, mirror neurons show congruence between the observed and executed action. This congruence can be extremely strict, that is the effective motor action (e.g. precision grip) coincides with the action that, when seen, triggers the neurons (e.g. precision grip). More recent experiments [19] have shown that neurons very similar to the “mirror” neurons recorded in area F5 are present also in the rostral part of the inferior parietal lobule (area PFG and PF). The present project will open new insights on different points. Mainly, it will provide new suggestions to understand the way in which visually perceived actions are mapped onto the observer motor repertoire. Several questions are still awaiting an answer. Among...
