Warblers – Butterflies of Bird World

WOOD WARBLERS - THE BUTTERFLIES OF THE BIRD WORLD  

April/May, 2013 issue  
  
 It  is early morning during the second week of May at Prince Edward Point,   the southeastern tip of Prince Edward County. The trees along the  groomed Point  Traverse trails are wet from the overnight rain. Yellow  warblers are everywhere,  and the much sought after northern parula with  its dazzling colours is so common  as to be considered almost a  nuisance bird. There are the finely marked  chestnut-sided warblers, and  as the sun works its rays through the mist, it  accentuates their  dazzling yellow crowns and chestnut side streaks. 
  
 This  is a fallout, something birders dream about finding along the shores   of Lakes Ontario and Erie – Presqu’ile Park, Rondeau Park, Point  Pelee…and  Prince Edward Point.  There may be thousands of birds here  this day as other  warblers land throughout the morning, exhausted by  the rainy, windy flight  across the lake. Several golden-winged warblers  hang by their feet like bats as  they methodically search the  undersides of the leaves for insect larvae.  Black-throated greens gasp  their wheezy notes, while black-throated blues call  from deeper within  the woods. A male appears in one tree, its pocket  handkerchief showing  on the wings in the form of delicate white patches.
  
 American  redstarts, their contrasting black and orange coats seem more   appropriate for a Halloween evening, and not a spring morning. There are   Tennessee warblers singing their staccato notes, yellowthroats  casually feeding  in the prickly ash as though they belong there rather  than in a wetland. Palm  warblers work the branches, their tails bobbing  up and down as though the  tracery of branches is too much for them to  maintain proper balance. There are  magnolia warblers - radiant against  the rising sun, Blackburnians with their  sunburst throats, ovenbirds  and yellow-rumped warblers - the list goes on. In  all, over 20 species  of warblers have arrived en masse to this diminutive point  of land, the  first land mass these neotropical migrants saw upon arrival. 
  
 These  small passerines are on a remarkable journey that has taken them all   the way from their wintering grounds in northern South America and  Central  America, and many will not stop until they reach the boreal  forests where they  will nest. Peninsulas of land that jut out into the  open lake are staging areas  where they will rest awhile, fatten up on  the spring supply of emerging insect  larvae, and then move on. After  departing their refuelling stations, that’s when  we start seeing them  locally in our backyards and  woodlots as they fan out and  browse their  way northward, feeding and singing, seemingly, for the love of   expressing their joy of life. Only on territory, will the males get more  serious  with their song and try to attract a mate. 
  
 There  is a standing joke among birders that Nashville warblers, Tennessee   warblers and Connecticut warblers are easily identified by their song,  since  they sing with a southern or New England accent. Actually they  are so named  because this is where early ornithologists first  discovered them, and named them  accordingly. While birds clearly do  have readily noticeable dialects, depending  on what part of the  continent you happen to be when you hear them singing, there  is nothing  about the song of the Nashville warbler that is twangy, or suggests   booze and broads and slipping around.
  
 That  bird species often deliver songs differently is well known. It doesn’t   really matter how a yellow warbler sings, we always know that it is a  yellow  warbler. Other warblers, too, have an incredible variety of  deliveries, but we  always know their identity because they have a  certain tonal quality that is  unique. Some warblers, like the northern  parula, offer two totally different  songs, and under what circumstances  they sing one over the other is not clearly  understood.
  
 During  a guided hike a few years ago, one person claimed she was having   difficulty understanding me as she was from Toronto and was adjusting to  my  “dialect.” I know about dialects. I have heard people talk in New  York City, and  I could listen to the New England dialect forever. I am  even aware that Ottawa  seems to have its own dialect. But I wasn’t  aware that the Prince Edward County  did also. I don’t think the folks  in Napanee have an accent, or those in  Tamworth, Kingston or  Harrowsmith. Perhaps they do, and I just don’t detect it.  
  
 Birds,  too, have dialects. We can suppose that individual species  understand  each other well enough when proclaiming their territories, but  whether a  straggler of the same species that wanders up from the south is   understood, we will never really know.
  
 Songs  of many species often incorporate arbitrary elements learned in the   individual’s lifetime. The basic song is there, but the young birds  learn  details of their songs from their fathers, allowing variations to  build up over  generations. As these warblers return to roughly the  same location each year,  and residential populations begin to build  over time, it is easy to see that  birds could develop what could be  referred to as a dialect, peculiar to their  geographical nesting  location each year to which they arrive.
  
 What  researchers have found though, is that some birds may be bilingual.   They will sing the local song that has been passed on to them by their  fathers,  but may occasionally sing a second dialect that they  apparently have learned  from members of their species passing through  and migrating farther north.  Researchers have also learned that local  birds produce a sound that carries best  in a particular sound  environment. So it would behoove a bird to hold on to the  song it has  learned from its father because this product of natural selection   enables it to project its song the greatest distance possible, to  attract that  special single female when he’s looking for a mate. 
  
 Fascinating  stuff indeed that we all too often fail to consider when we are   watching these little butterflies of the bird world flitting about the  branches  on their way to the northern forests. Think about their  destinations and their  songs when the warbler family passes through  your backyard this spring.  Consider, too, that only days earlier they  had been associating with resident  bananaquits and motmots in Costa  Rica. 
  
 For more information on birding and nature and guided hikes, check out the  NatureStuff website at www.naturestuff.net 
  
 Terry Sprague lives in Prince Edward County and is self-employed as a  professional interpretive naturalist.