BIRD TO­POG­RA­PHY IN A NUT­SHELL

Bird Watching (UK) - - Id Secrets -

Birds are cov­ered in feath­ers. These mod­i­fied scales have evolved to pro­vide birds with the power of flight, warmth, con­tour and colour but also per­form rel­a­tively unseen func­tions such as act­ing as ‘whiskers’ around the gape, or as ‘eye­lashes’. When de­scrib­ing a bird as part of the iden­ti­fi­ca­tion process, it is use­ful to be aware of the main pat­terns of dis­tri­bu­tion of feath­ers on any given bird. Birds’ feath­ers ap­pear in re­gions or tracts, which are more or less con­sis­tent across the dif­fer­ent species. The ar­eas la­belled on ‘to­po­graphic’ maps of birds cor­re­spond to these tracts and are es­sen­tially trans­fer­able across the dif­fer­ent groups; which is one rea­son why they are so use­ful. De­tailed de­scrip­tions of birds are usu­ally given from front to back, so let’s look at the dif­fer­ent main feath­ers in that or­der. On the head there is the fore­head and crown in the cen­tral area (which can be em­pha­sised by lat­eral and me­dian crowns stripes. Be­neath the crown and above the eye and ear coverts are the su­peri­cilia, the pale ‘eye­brow’ above the usu­ally darker eye­stripe (which ap­pears to pass through the eye). There is of­ten a nar­row ring around the eye called the ey­e­r­ing. In front of the eye, the re­gion is called the lores. The ‘cheeks’ of a bird are called the ear coverts, the lower part of which is of­ten marked by a dark mous­tachial stripe. Be­neath this there is a pale sub­mous­tachial stripe and be­neath that of­ten a dark stripe called a malar stripe (or lat­eral throat stripe), be­neath which is the self-ex­plana­tory throat. The lower back of the neck is the nape, the cen­tre of the back be­hind this the man­tle. Fur­ther back is the back, then the rump and then the up­per tail coverts and lastly the longer tail feath­ers also called rec­tri­ces. Un­der the throat is the breast, then the belly, which af­ter the legs is called the vent, and un­der the tail is the un­der­tail coverts. The rest of the bird is ba­si­cally wing feath­ers. These con­sist of the shoul­der feath­ers, called the scapu­lars, the wing coverts which are (from the shoul­der down) called lesser, me­dian and greater coverts with the alula and pri­mary coverts tucked un­der the greater coverts at the lead­ing edge of the wing (around the bend). The in­ner longer, stiffer flight feath­ers (aka remiges) are called ter­tials, the mid­dle sec­tion the sec­on­daries and the outer (usu­ally long­est) flight feath­ers (which can make the point of the wing) are the pri­maries. These dif­fer­ent wing feath­ers are at­tached to dif­fer­ent bones in the wing, but that need not trou­ble you!

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