[LTER-hbr-im] questions re Hubbard Brook bird population changes (website raw data vs. trends described in your new HB book)

[Mary Martin]

Nora, I see that you cc'd Dick Holmes. That's good. He'll either be able to 
answer your question or bring other bird folks into the conversation. I 
upload contributed data to oir database, and data download queries pull 
data from there. I've been known to make mistakes before, so I've gone back 
to the original data file sumitted to me, and I see those same patterns in 
hairy woodpecker and Swanson's thrush. And a spot check confirms that the 
data file sumitted matches website downloaded data. And just to make sure 
we're on the same page,  you are talking about the bird area dataset, and 
not valleywide?
Mary

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On June 16, 2017 8:43:49 PM Nora Hanke <nhanke at antioch.edu> wrote:

> Hello
>
> I am a graduate student in Environmental Studies at Antioch University and 
> have been enjoying your' wonderful Hubbard Brook book. I am researching 
> some aspects of the HB studies and don't understand what appear to be data 
> discrepancies.
>
> Specifically, I am confused by looking at the raw data published on the HB 
> website in comparison to the species trends documented in Hubbard Brook 
> (2016). (I know the latter are for a period ending in 2013.)
> For example, Hairy Woodpeckers are described as fairly stable, but 
> comparing their numbers in the first 4 years of the study with the period 
> 2012 through 2015, they appear to have doubled. Swainson's Thrushes are 
> described as stable, but the average of their no.s in recent years are 
> under a quarter of their abundance in an average of the study's first few 
> years. Philadelphia Vireos are described as declining (rather than 
> disappeared), but they have not been noted in the HB study site since 1982, 
> according to the website's data. Similarly, Veeries are described as 
> declining, but were last counted in 2005.
> I am guessing that the HAWO and SWTH number changes are not statistically 
> significant, or else your threshold for defining population change is 
> greater than the population changes noted in the two comparison periods I 
> am studying. But I really don't get the interpretation for the birds that 
> are gone - according to the HB website published abundance data.
> I apologise if I am obtuse or show a horrific lack of understanding 
> biostatistics or interpreting raw data. I will be studying biostatistics 
> next semester. In the meantime, I am currently writing a paper on your bird 
> studies and deeply mystified.
> I would appreciate some clarification, if you have time to respond.
> Thank you!
>
> Nora E Hanke
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