What Do The Stats Tell Us?
In our list of ways to keep the statistics, #s 3 & 4 are by the number of days and number of hours. It should be obvious that at the end of the count we can count the hours and days to see the combined efforts of the counters. Not all counters were present on all days, or for all hours of a particular day. Counters and visitors come and go, but counters are volunteers who will help to spot and ID the birds being seen - and that may include all birds, even non-raptors. Not all visitors are counters. Some come to take pictures, view the scene, and some are just curious how a hawk watch works. Some are neighbors, and some are tourists. But all counters are, to some degree, birders- many with a particular love of raptors, but most have varied loves of all things natural. And each volunteer contributes the number of hours and days he or she is able. Not all volunteers keep records. (I don't. I depend on Jimmy for records, and I do spotting and identification, and concentrate on the blog and media.) Not all counters who keep stats keep all the stats. Most keep only the stats for their own volunteer hours. So the basis for the hours and days stats is a combined effort.At some point, it became obvious to Bill that there was not a unified single record of everyone's stats. And Jimmy picked it up, and consistently continued it. And we have to admit that there are some stats missing from our 24 year record. But we can assure you, that Jimmy has tried to accumulate all the data he was able to obtain. He made it his own obsession to keep up with everyone's data. Bill had accumulated it from everyone from the beginning, and Jimmy felt it necessary to also have a complete record for comparisons and in case of loss. I don't think Jimmy ever thought we would look back over 24 years at some point and be able to make a panoramic view of all those efforts.
Several of the counters who kept data began to send emails to one another and/or share the stats each day. So several have large parts of the data. But to my knowledge not all have all the data. Yet Jimmy has consistently kept data and began to send it to TN-Birds after a certain point. Bill had previously sent it to Hawk Migration Association of North America..HMANA. It is their combined data that makes the whole.
So many people wanted to see the numbers, I realized that the best way to make it viewable was to begin a website dedicated to it. And although the web-page doesn't go back to dailies in the beginning, I am able to display the results of the records these men kept over the course of time. A list of other counters who kept and compared lists, and added hours and statistics would have to include Jim Rowell, Harold Birch, & Bill Holt as counters who consistently over the years have kept records. Many others have shared the information and data they kept when they were there, but the bulk of information is held among these few men. And to them I give applause for making that data possible.
So many have helped us and put in hours, that I would not be able to name them all, but to them we give a great deal of thanks. For they are those who gave us "hours and days" to report. It is the volunteers who are responsible for the dedication to spending time counting hawks that make any data what-so-ever to be possible. Jimmy, Bill, Harold, Bill Holt, and I could not have accomplished the counts alone!
Soooooo, what do the hours and days stats show us? I was surprised to find that I couldn't make general statements after doing the chart and making comparisons. We might have expected to find that in years of extra hours, we would also have more raptors seen. Not so. But this is an example of answering questions we had or some have asked. If you are curious, you might find the breakdown as interesting as we did.
Let me start by reposting the numbers chart, with percent BW's and years, as a simple reminder of the numbers of raptors seen listed from most to least, and the years they were seen. Last post I broke that data down and did percentage comparisons, with what could be gleaned from that info. Here is that chart:
Next I want to rearrange that data by hours and days. It makes sense to skip doing most to least days, and go directly to most to least hours. So that is how the next chart is arranged.
In my last post, Jimmy said we must still take in to consideration the number of hours/days to make accurate calls on the data summaries. So I formed the chart to relate directly back to this chart, while changing it's order by year to reflect highs and lows of hours.
As I said before, our expectations didn't meet up to what the data reflected.
If the side bar interferes with being able to see the chart, click on the picture and it will bring up only the charts in this article as pictures. You can view them clearly without overlap.
On the top 4 most hours spent, the hours exceed 300 - 305.5, 325, 331, and 341 with the birds per hour ranging from about 13/hr to about 10/hr. And the percent of BW's in those high hour years is in the upper middle range, of from about 43% to about 68%. As you see, the numbers of hours didn't produce the highest percents on BW's, as we might expect, but it also didn't produce the lowest, as it might seem. but as we discussed in our last blog, even when the hours were spent in October through December to capture greater numbers of other species, the average percent of BW's each year still held at over 50%. Which holds true here, in the hourly counts as well.
We can also compare these Total Raptor Numbers in the far right column, to the average number of raptors seen per year, from out last post which was 3,480 birds/yr, and see that these high numbers of hours also produce average bird count years - 3312, 2943, 3554 and 3833. So the numbers of hours spent do not reflect higher numbers in raptor totals. I would need to put in each raptor to find out which if any of the raptors this does not hold true for. And I would think the answer would be obvious. Than any hours spent in October through December would elevate the percentages for the species that migrate during those months. But since we are considering all birds and all hours, we have leveled the field a bit.
Now let's look at those 3 lowest years and WOW, look what we find! Those years spent with the fewest hours, were NOT the lowest bird counts. In fact, in spite of the days and hours being so similar, the total raptor counts were very different - 1881, 2677, and 5511 total raptors. In fact the percents of average number of hours per day were only 3 to 4 hours. Now that average definitely does not reflect actuals. There most certainly were long days to have counted 5500 birds in 2009. What those averages show us, is the hours were similar, the percents of hours per day were similar and the number of days were similar but the counts were very different! In fact, 2009 was the very best year for a birds/hour average! 108.5 birds per hour average. Some where in that year there must have been a few large kettles! LOL It would become very difficult indeed to actually count 108 birds per hour over 13 days, every day every hour. Even over a few days! (Thankfully, hawks come in groups with breaks in between sometimes.) But we are able to make the comparisons in an usual way, with eye opening results.
Now let's look at some specifics on the chart:
1. The total number of hours spent in 24 years was - 4546.75 hours. Didn't seem like enough. Seemed more like 10,000. Haha.
2. The total number of days spent was -905 days. If we divide the days into the hours we get:
3. The average number of hours per day is - 5.024 hr/day. That's a good median, when we think about how some days are shortened by rain, or available hours to spend there. Where as some days are from 8am to 6pm. If I did the same calculations for only September, the per hour tots would be higher. But we are using the grand totals for all of our charts.
4. The average number of hours per year is - 189.45 hours. I thought this was all a bit superfluous until I was able to use that number to compare it to the whole chart. I found that the middle range hours were very near that number, and it was accurate to making comparisons in middle range years.
5. The grand total of birds divided by the grand total of hours averages to - 18.37 or about 19 birds per hour over the entire 24 years.
Column 3 is where I took the total number of raptors for each year, and divided by the number of hours it took to count them, and I came up with an average of birds/hour for each individual year. Because of the amounts of birds after the decimals being parts of birds, when I added them all by rounding up or down in the 4th place after the decimal, the division of birds per hour by this method came up to over 22 raptors/hr. A little more than the 19 above. So I dropped that average all together, since it has a reason for being inflated. But the individual years enlighten us to which years were more or less birds/hr being seen.
So let's investigate the wide variety of things this info can show us. It makes it clear how the hours really don't affect good or bad results as we first thought. We already said that 2009 was the best year for raptors/hour. I have asked Jimmy to help me look up the records and see if there is an error on the chart, or if I have transposed something wrong. Because this figure is so far above the next best Bird/hour. This alone is a good reason for doing such a piece of data comparison. It might show obvious errors in records. It's good for cks and balances, and to make the odd jump out at you. Everything I have been able to ck so far, indicates the data is correct. But it requires that we go back into the books to verify. And we wouldn't do that without a good reason.
The chart also shows us that this year was the WORST Birds/hour season, at about 7.9. Whereas,we saw in the last blog that 2016 fared pretty well against other years in numbers of birds seen, and it left me wondering why we thought it was such a bad year, this bit of info tells the story in a nutshell. It WAS the worst year in birds seen per hour. Yet it still holds it's own when compared to other years when the most hours were spent counting, when the birds/hour fall between 8 and 10. Once again, we know why. While BW's come in droves, others species are counted mostly one by one. And the result is it takes more hours to count them. Another reason why it is difficult to hold the attention of casual hawk watchers into the less productive hours after BW season.
For so many reasons, we knew the birds were just not there, although hours were spent looking for them in 2016. It certainly didn't take a chart of comparisons to know it. It was very obvious to us that our efforts weren't producing numbers. LOL
Just as the least birds per hour fall into the top of the chart with the most hours spent counting..the most birds per hour fall into the second half of the chart where the fewest hours were spent counting. No surprise there. Besides 2009's huge 108 bird/hour, the greatest averages were 57+ birds/hr in 2012 with 4905 tot raptors seen; About 54 birds/hr in 2010 with a tot of 2677 raptors seen; and about 49 birds/hour in 2015, which was the largest raptor count year with 8618 total raptors seen. Comparing their hours looks like comparing the least number of hours- the results are very diverse.
86 hrs, 50 hrs. and 177 hrs spent respectively counting. No similarities again to be drawn in how hours reflect more or less birds on average.
About 25% of the years we spent less than 4.5 hours daily. Obviously, all other years exceeded 4.5 hrs/day on average. I repeat...75% of the days, there were over 4.5 hours/day average spent collectively, watching for raptors.
The most hours/day average fell in 2004 when we spent 53 days and 331 hours to see 2943 Raptors. This is the second most hours spent, with the number of raptors seen falling about 500 birds below the 3480, average birds per year we discussed earlier. Yet it is still mid range, not the least number of raptors seen by far. The least hrs/day did however produce the aforementioned most birds/hour in 2009 - over 108.5 average. That was 3.13 hrs/day in 13 days. 5511 Raptors with 95% of them being BW's. A great year anyway you look at it, if there are not stats errors. And maybe if there are. Yet it reinforces the obvious - that the birds/hour increases when the data revolves around BW's almost exclusively.
I think the only thing I haven't covered is that the most days spent on the watch were 62 in 1998, with
325 hours, 10.9 birds/hr., 5.24 average hours/day, and 3554 total raptors seen, of which 42.5% were Broad-wings. This is a good example of how you can read the chart. It follows the percents we have already established. More hours means fewer birds per hour, but the daily average hrs/day is almost on the money (5.024).The raptor count total is a little over the yearly average of 3480 raptors. but under the average of 54% BW's with 42.5% seen.
The least number of days spent was 12, in 2011 with also the least number of hours spent - 49.5 hrs.
There were 38 birds/hrs seen in an average of 4.13 hrs/day. 1881 Raptors were seen with an average of 96.9 % BWs. That was one of the 25% of days under 4.5 hrs/day was spent watching, but was the next to the highest percent BW's seen in a year. 1881 fell way below the yearly average of 3480 raptors, but was well over the average of 18.37 birds/hours.
What did I learn about the hourly stats? What we already knew, but is now confirmed. That is: Each year is decidedly different, cannot be met with expectations and holds a uniqueness that helps to keep us coming back to it year after year, regardless of how many hours we have to give, or how few. Each day is new on the hawk watch. Each hour unwraps it's jewels - 1000 or none...it just depends on how many hawks happen to be flying by. And if we are there to count them, then they can go into our data. Which will change next year for certain. Are there records we would like to set? More days, more hours, more hawks seen??? I don't think so. I am sure Bill would love to see more coverage past BW season...but that's about all we dream of. We've experienced some highs and some lows. But it all averages out to one exceptional good time. And we have learned a high percentage of things we didn't know before we began! We've seen 100% more than we dreamed we could. We've been blessed with the best company that can be had. We've seen the earths routines affirmed again and again, and found peace in that. No gain or loss of data can ever take any of that away.
And finding averages allows us to say...this year or that is above average her or below average there. So then it remains to say, which you prefer, more birds per hour, or more birds per year. And that varies greatly. So if you love the years when over 4000 birds were seen, those will be your "best" years. But if you prefer the years when you spend less time, but the birds just keep streaming through when you are there, the more birds per hour, when you spend fewer hours there, will be your "best" year. Averages only allow us to see what is greater or lesser when applied to certain criteria. Therefore, with hours/days averages the answers are very vari-able!
Perhaps some of you will see something in the charts that I didn't mention here. It might be worth posting. Even if it's curious, not momentous. I told you I was just being my analytic self. A less analytic eye might glean something monumental from all this. E-mail Jimmy with an LOL and let us know. For those who preferred not to even read any of this, you may never know that I am perfectly fine with that. Not everyone loves the boring stuff. It doesn't hurt my feelings a bit. But I have grown, and have found a bit of peace in seeing the numbers in a new way.
Please Please Please sent new watchers our way, if there is someone who might love hawks well enough to put in hours in the future. We absolutely need eyes to the skies and people who don't mind spending hours, to see Raptors and are willing to
KEEP LOOKING UP
2 more simple posts and we close the blog on Fall 2016. Thanks for reading.
ps. somehow my computer got set onto overwrite, so I will not make edits to this blog. I am afraid it would result in losing large amounts of what I have written. So sorry. Jimmy will hate it more than you will. I cannot figure out how to get it off of overwrite. Maybe in the future I will do a reread and an edit. Thanks for your patience.
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