The Decline

Edgar T. Jones 6115 141st Street Edmonton, Alberta T6H 4A6

continent, would eventually have drastic effects on shavea long becometime bander very concernedofsome 35 aboutyears theexperience, staggering I ecological systems. The effect of DDT has been well declineof somespecies of passefinebirds, particularly the documented on many species, and we must remember warblers. To demonstrate this decline I have chosen the that many of the chemicalsused today are many times TennesseeWarbler, which a few years ago appeared to more powerful than DDT, Dieldrin beinga goodexample. be the most abundant migrant in this part of the country. These are which nest primarily in the north central Having personallyvisited CostaRica, I am alsoof the opi- boreal forest regionsof Canada and migrate through this nion that the vast and continuing destruction of the area in August to winter quarters in Central or South tropical rain forests throughout Central and . It is the opinion of this writer that the popula- America must be having some detrimental effects on the tion drop in TennesseeWarblers since 1971 has been not swarms of passerineswhich pass through or winter in less than 85-90% {Jones,19841 . those areas.

My permanent banding sectionis located on the edge of My third major concern and opinion is that the millions a north/southoriented ravine throughwhich flows White upon millions of wild/domestic house cats in North Mud Creek. At this point the ravine and creek enter the America are also a factor. Accordingto recently publish- North Saskatchewan River of north central Alberta which ed figuresthere are over 80 million domesticcats on North flows in a northeasterly direction, eventually emptying America, many of which are allowed outside at intervals into Hudson's Bay. during the day or night. If onecat onlytakes just one a year, we have lost over 80 million birds. Passerinesare It is important to point out that over the period of 1978-85 those birds most likely to suffer, particularly ground there has been little or no change in the banding station feeders. surroundings.All nets have been placed in the same loca- tion each year and detailed records kept of the number In additionto the above,the TennesseeWarbler's breeding of birds caught in each net. Each year I have used 14 or populations could have been affected to some extent by 15 one and one-half inch mesh mist nets along with a the hundredsof forest fires burning throughoutNorthern 'water drip' Cohassetwarbler trap. Alberta over the past few summers. AlthoughI have kept detailedbanding records since 1971 It would be interestingto know if other bandersin various the years 1978-85were used as the bandinghours record- parts of have experiencedsimilar declines. ed were more consistent with the migration of the warblers. The month of August is the main migration Acknowledgements period for most of the warblers passingthrough this area of Canada. I wishto thank the following forreviewing thisarticle and for their assistancerendered. Dr. David E DeSante, Table 1 gives the complete picture of the declines while Director of Landbird Research,Point Reyes Bird Obser- Figures 1 and 2 show the recorded declines, (1) of all vatory and Dr. L. Richard Mewaldt. passerinescaught over the 1978-85 period and (2) the Literature Cited specific decline of TennesseeWarblers over the same period. Jones, Edgar % Concerned note from Edgar T. Jones, Alberta Naturalist, Volume 14, Number 4, December For many years it has been the opinion of this observer, 1984. that the billions of gallons of chemical insecticides,her- bicides, etc. scatteredthrough the world, including our

Table 1. Banding Records During August TOTAL NET TOTAL CATCH RATE TENNESSEE WARBLERS YEAR HOURS BIRDS PI100 NET HOURS WARBLERS PI100 NET HOURS

1978 2,353 1,979 84 1,060 45.0 1979 4,876 1,601 33 890 18.3 1980 3,556 1,820 51 635 17.9 1981 2,385 596 25 182 7.6 1982 3,845 702 18 190 4.9 1983 4,212 637 15 168 4.0 1984 1,912 214 11 32 1.7 1985 4,800 427 09 33 .68

Page 74 North American Bird Bander Vol. 11, No. 3 Figure 1. The downward trend calculated on #/100 TennesseeWarbler net hours. Figure 2. Banding catch rate during August 1978-1985. Birds caught during August. Net hours 1978-1,979 1978 -2,353 1979- 1,601 1979- 4,876 1980 -1,820 1980-3,556 1981 - 596 1981 -2,385 1982 - 702 1982 -3,845 1983- 637 1983 -4,212 1984- 214 1984- 1,912 1985- 427 1985- 4,800

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YEARS YEARS 1978 79 80 81 82 83 84 85 1978 79 80 81 82 83 84 85

{Western)

Jul.-Sept. 1986 North AmericanBird Bander Page 75